OXIDATION CATALYST COMPRISING A PLATINUM GROUP METAL AND A BASE METAL OXIDE

Abstract

The present disclosure relates to oxidation catalyst compositions comprising a platinum group metal (PGM) component comprising palladium, platinum, or a combination thereof; a manganese component; and a first refractory metal oxide support material comprising zirconia; catalytic articles; and exhaust gas treatment systems, as well as methods of making and using such oxidation catalyst compositions, for example, to reduce formaldehyde levels in engine exhaust emissions.

Claims

1. An oxidation catalyst composition comprising: a platinum group metal (PGM) component comprising palladium, platinum, or a combination thereof; a manganese component; and a first refractory metal oxide support material comprising zirconia.

2. The oxidation catalyst composition of claim 1, comprising manganese in an amount by weight, on an oxide basis, from about 0.1% to about 90%, based on the weight of the first refractory metal oxide support material.

3. The oxidation catalyst composition of claim 1, wherein the manganese component is supported on the first refractory metal oxide support material.

4. The oxidation catalyst composition of claim 1, wherein the first refractory metal oxide support material comprises zirconia in an amount by weight from about 1% to about 99%.

5. The oxidation catalyst composition of claim 1, wherein the first refractory metal oxide support material further comprises alumina, silica, ceria, titanium oxide, silica-doped alumina, silica-titania, silica-zirconia, yttrium-zirconium, manganese-zirconium, tungsten-titania, zirconia-titania, zirconia-ceria, zirconia-alumina, manganese-alumina, lanthanum-zirconia, lanthanum-zirconia-alumina, magnesium-alumina oxide, and combinations thereof.

6. The oxidation catalyst composition of claim 1, wherein the zirconia in the first refractory metal oxide support material is doped with lanthanum in an amount by weight from about 1% to about 40% on an oxide basis, based on the weight of the zirconia.

7. The oxidation catalyst composition of claim 1, further comprising a base metal oxide chosen from oxides of cerium, iron, cobalt, zinc, chromium, molybdenum, nickel, tungsten, copper, magnesium, antimony, tin, lead, yttrium, and combinations thereof.

8. The oxidation catalyst composition of claim 7, wherein the base metal oxide is supported on the first refractory metal oxide support material.

9. The oxidation catalyst composition of claim 7, wherein: the base metal oxide is an oxide of ceria, and the ceria is present in an amount up to about 99% by weight, based on the weight of the first refractory metal oxide support material.

10. The oxidation catalyst composition of claim 1, comprising: manganese in an amount by weight, on an oxide basis, from about 1% to about 60%, based on the weight of the first refractory metal oxide support material; and ceria in an amount from about 1% to about 99%, by weight, based on the weight of the first refractory metal oxide support material.

11. The oxidation catalyst composition of claim 1, wherein: the palladium is loaded on the first refractory metal oxide support in an amount by weight from about 0% to about 10%, based on the weight of the first refractory metal oxide support; the platinum is loaded on the first refractory metal oxide support in an amount by weight from about 0% to about 10%, based on the weight of the first refractory metal oxide support; and wherein at least one of the platinum or the palladium is present in an amount by weight of about 0.1% or greater, based on the weight of the first refractory metal oxide support material.

12. The oxidation catalyst composition of claim 1, wherein the PGM component comprises a combination of platinum and palladium.

13. The oxidation catalyst composition of claim 12, wherein a ratio of palladium to platinum by weight is from about 100 to about 0.01[[.]], or from about 1 to about

14. (canceled)

15. The oxidation catalyst composition of claim 1, further comprising a second refractory metal oxide support material, wherein the second refractory metal oxide support material optionally comprises alumina, silica, zirconia, titania, ceria, silica-doped alumina, silica-titania, silica-zirconia, yttrium-zirconium, manganese-zirconium, tungsten-titania, zirconia-titania, zirconia-ceria, zirconia-alumina, manganese-alumina, lanthanum-zirconia, lanthanum-zirconia-alumina, magnesium-alumina oxide, or a combination thereof and wherein the second refractory metal oxide support material optionally comprises a base metal oxide chosen from oxides of cerium, iron, cobalt, zinc, chromium, molybdenum, nickel, tungsten, copper, magnesium, antimony, tin, lead, yttrium, and combinations thereof.

16. (canceled)

17. (canceled)

18. The oxidation catalyst composition of claim 15, wherein the PGM component is supported on the second refractory metal oxide support material in an amount by weight from about 0.1% to about 10%, based on the weight of the second refractory metal oxide support material.

19. The oxidation catalyst composition of claim 15, wherein the second refractory metal oxide support material comprises alumina or zirconia.

20. The oxidation catalyst composition of claim 19, wherein the zirconia in the second refractory metal oxide support material is doped with lanthanum in an amount by weight from about 0.1% to about 40%, on an oxide basis, based on the weight of the zirconia.

21. The oxidation catalyst composition of claim 15, wherein the second refractory metal oxide support material is substantially free of lanthanum.

22. The oxidation catalyst composition of claim 15, wherein the second refractory metal oxide support material comprises manganese.

23. The oxidation catalyst composition of claim 15, wherein the manganese component is supported on the first refractory metal oxide support material, and the PGM component is supported on the second refractory metal oxide support material optionally in an amount from about 0.1% to about 10% by weight, based on the weight of the second refractory metal oxide support material.

24. (canceled)

25. The oxidation catalyst composition of claim 15, wherein: the manganese component is manganese oxide, supported on the first refractory metal oxide support material in an amount by weight, on an oxide basis, from about 0.1% to about 40%, based on the weight of the first refractory metal oxide support material; and the PGM component is supported on the second refractory metal oxide support material, wherein the second refractory metal oxide support material is chosen from alumina, silica-doped alumina, titania, titania-doped alumina, zirconium doped alumina, zirconia, and zirconia doped with from about 1% to about 40% by weight of lanthana, based on the weight of the zirconia.

26. The oxidation catalyst composition of claim 25, wherein the first refractory metal oxide support material further comprises ceria in an amount by weight from about 1% to about 50%, based on the weight of the first refractory metal oxide support material.

27. The oxidation catalyst composition of claim 1, wherein the oxidation catalyst composition is substantially free of copper.

28. A catalytic article comprising a substrate having an inlet end and an outlet end defining an overall length, and a catalytic coating disposed on at least a portion thereof, the catalytic coating comprising a first washcoat and a second washcoat, wherein: the first washcoat comprises a manganese component and a first refractory metal oxide support material comprising zirconia, wherein the manganese component is supported on the first refractory metal oxide support material as manganese oxide or a mixed oxide; and the second washcoat comprises a platinum group metal (PGM) component comprising palladium, platinum, or a combination thereof, and a second refractory metal oxide support material, wherein the PGM component is supported on the second refractory metal oxide support material.

29-50. (canceled)

51. A catalytic article comprising a substrate having an inlet end and an outlet end defining an overall length, and a catalytic coating disposed on at least a portion thereof, the catalytic coating comprising a first washcoat, a second washcoat, and a third washcoat, wherein: the first washcoat comprises a manganese component and a first refractory metal oxide support material comprising zirconia, wherein the manganese component is supported on the first refractory metal oxide support material as manganese oxide or a mixed oxide; the second washcoat comprises a base metal oxide component comprising ceria, manganese oxide, zirconia, lanthanum oxide, copper oxide, or a combination thereof, and a second refractory metal oxide support material, wherein the base metal oxide component is supported on the second refractory metal oxide support material; and the third washcoat comprises a platinum group metal (PGM) component comprising palladium, platinum, or a combination thereof, and a third refractory metal oxide support material, wherein the PGM component is supported on the third refractory metal oxide support material.

52-69. (canceled)

70. A formaldehyde oxidation catalyst composition comprising: a refractory metal oxide support material comprising zirconia; manganese in an amount by weight, on an oxide basis, from about 1% to about 30%, based on the weight of the refractory metal oxide support material; and ceria in an amount from about 0% to about 30%, based on the weight of the refractory metal oxide support material, wherein the formaldehyde oxidation catalyst composition is substantially free of copper.

71-73. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to provide an understanding of certain embodiments of the disclosure, reference is made to the appended drawings, in which reference numerals refer to components of exemplary embodiments of the disclosure. The drawings are exemplary only, and should not be construed as limiting the present disclosure. The disclosure described herein is illustrated by way of example and not by way of limitation in the accompanying figures. For simplicity and clarity of illustration, features illustrated in the figures are not necessarily drawn to scale. For example, the dimensions of some features may be exaggerated relative to other features for clarity. Further, where considered appropriate, reference labels have been repeated among the figures to indicate corresponding or analogous elements.

[0047] FIG. 1A is a perspective view of a honeycomb-type substrate, which may comprise an oxidation catalyst composition in accordance with the present disclosure.

[0048] FIG. 1B is a partial cross-sectional view enlarged relative to FIG. 1A and taken along a plane parallel to the end faces of the substrate of FIG. 1A, which shows an enlarged view of a plurality of the gas flow passages shown in FIG. 1A, in an embodiment wherein the substrate is a flow-through substrate.

[0049] FIG. 2 is a cutaway view of a representative wall-flow filter.

[0050] FIGS. 3A, 3B, and 3C are non-limiting illustrations of possible coating configurations.

[0051] FIG. 4 is a schematic depiction of an embodiment of an emission treatment system in which a DOC catalyst article of the present disclosure is utilized.

[0052] FIG. 5 is a cartoon depiction of the composition loading for test articles according to certain embodiments of the disclosure.

[0053] FIG. 6 is a graph depicting % NO.sub.2/NO.sub.x versus inlet temperature for Pt/Pd catalysts on various supports with 5% Mn.

[0054] FIG. 7 is a graph depicting % NO.sub.2/NO.sub.x versus inlet temperature for Pt/Pd catalysts on various supports with 25% Mn.

[0055] FIG. 8 is a chart depicting NO.sub.2/NO.sub.x yield at 300 C. and 250 C. for aged Pt/Pd (2/1) powder samples (9% La on Zr (reference); 10% Y on Zr).

[0056] FIG. 9 is a chart depicting NO.sub.2/NO.sub.x yield at 300 C. and 250 C. for aged Pt/Pd (2/1) powder samples (9% La on Zr (reference); 10% Si/ZrO.sub.2).

[0057] FIG. 10 is a chart depicting NO.sub.2/NO.sub.x yield at 300 C. and 250 C. for aged Pt/Pd (2/1) powder samples (9% La on Zr (reference); Zr75/Mn24).

[0058] FIG. 11 is a chart depicting NO.sub.2/NO.sub.x yield at 300 C. and 250 C. for aged Pt/Pd (2/1) powder samples (9% La on Zr (reference); 10% Si on Ti).

[0059] FIG. 12 is a chart depicting NO.sub.2/NO.sub.x yield at 300 C. and 250 C. for aged Pt/Pd (2/1) powder samples (9% La on Zr (reference); 5% Si on Al).

[0060] In some embodiments, the present disclosure generally provides an oxidation catalyst composition for use in an exhaust gas treatment system comprising a compression ignition internal combustion engine, the composition comprising a platinum group metal (PGM) component comprising palladium; a manganese component; and a first refractory metal oxide support material comprising zirconia. Surprisingly, it has been found that the addition of manganese onto a lanthana-doped zirconia support was beneficial for both FIC conversion and. NO.sub.2 yield. Unexpectedly, while the further addition of copper to the Mn/LaZr support resulted in enhanced conversion of CO, this addition compromised HC conversion and NO.sub.2 yield.

[0061] The presently disclosed subject matter now will be described more fully hereinafter. The disclosed subject matter may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

Definitions

[0062] As used herein, the articles a and an herein refer to one or to more than one (e .g., at least one) of the grammatical object. Any ranges cited herein are inclusive. The term about used throughout is used to describe and account for small fluctuations, For instance, about may mean the numeric value may be modified by 5%, 4%, 3%, 2%, 1%, 0.5%, 0.4%, 0.3%, 0.2%, 0.1% or 0.05%. All numeric values are modified by the term about whether or not explicitly indicated. Numeric values modified by the term about include the specific identified value. For example, about 5.0 includes 5.0.

[0063] As used herein, the term abatement means a decrease in the amount, caused by any means.

[0064] As used herein, the term associated means, for instance, equipped with, connected to, or in communication with, for example, electrically connected or in fluid communication with or otherwise connected in a way to perform a function. The term associated, as used herein, may mean directly associated with or indirectly associated with, for instance, through one or more other articles or elements.

[0065] As used herein, average particle size is synonymous with D.sub.50, meaning half of the population of particles has a particle size above this point, and half below. Particle size refers to primary particles. Particle size may be measured by laser light scattering techniques, with dispersions or dry powders, for example, according to ASTM method D4464, D.sub.90 particle size distribution indicates that 90% of the particles (by number) have a Feret diameter below a certain size as measured by Scanning Electron Microscopy (SEM) or Transmission Electron Microscopy (TEM) for submicron size particles; and a particle size analyzer for the support-containing particles (micron size).

[0066] As used herein, the term catalyst refers to a material that promotes a chemical reaction. The catalyst includes the catalytically active species and the carrier that carries or supports the active species.

[0067] As used herein, the term functional article means an article comprising a substrate haying a functional coating composition disposed thereon, in particular a catalyst and/or sorbent coating composition.

[0068] As used herein, the term catalytic article means an article comprising a substrate having a catalyst coating composition.

[0069] As used herein, CSF refers to a catalyzed soot filter ; which is a wall-flow monolith. A wall-flow filter consists of alternating inlet channels and outlet channels, where the inlet channels are plugged on the outlet end and the outlet channels are plugged on the inlet end. A soot-carrying exhaust gas stream entering the inlet channels is forced to pass through the filter walls before exiting from the outlet channels. In addition to soot filtration and regeneration, a CSF may carry oxidation catalysts to oxidize CO and HC to CO.sub.2 and H.sub.2O, or oxidize NO to NO.sub.2 to accelerate downstream SCR catalysis or to facilitate the oxidation of soot particles at lower temperatures. A CSF, when positioned behind a TAT catalyst, can have a H.sub.2S oxidation functionality to suppress H.sub.2S emission during the LNT desulfation process. An SCR catalyst can also be, in some embodiments, coated directly onto a wall-flow filter, which is called a SCRoF.

[0070] As used herein, DOC refers to a diesel oxidation catalyst, which converts hydrocarbons and carbon monoxide in the exhaust gas of a diesel engine. In some embodiments, a DOC comprises one or more platinum group metals such as palladium and/or platinum and a refractory metal oxide support material.

[0071] As used herein, LNT refers to a lean NO.sub.x trap, which is a catalyst containing a platinum group metal, ceria, and an alkaline earth trap material suitable to adsorb NO.sub.x during lean conditions (for example, BaO or MgO). Under rich conditions, NO.sub.x is released and reduced to nitrogen.

[0072] As used herein, the phrase catalyst system refers to a combination of two or more catalysts, for example, a combination of a present oxidation catalyst and another catalyst, for example, a lean NO.sub.x trap (LNT), a catalyzed soot filter (CSF), or a selective catalytic reduction (SCR) catalyst. The catalyst system may alternatively be in the form of a washcoat in which the two or more catalysts are mixed together or coated in separate layers.

[0073] The term configured as used in the description and claims is intended to be an open-ended term, as are the terms comprising or containing. The term configured is not meant to exclude other possible articles or elements. The term configured may be equivalent to adapted.

[0074] In general, the term effective means, for example, from about 35% to 100% effective, for instance from about 40%, about 45%, about .50% or about 55% to about 60%, about 65%, about 70%, about 75%, about 80%. about 85%, about 90% or about 95%, regarding the defined catalytic activity or storage/release activity, by weight or by males.

[0075] As used herein, essentially free means little or no or no intentionally added, and also having only trace and/or inadvertent amounts. For instance, in certain embodiments, essentially free means less than 2 wt. % (weight %), less than 1.5 wt. %, less than 1.0 wt. %, less than 0.5 wt. %, less than 0.25 wt. %, or less than 0.01 wt. %, based on the weight of the indicated total composition.

[0076] As used herein, the term exhaust stream or exhaust gas stream refers to any combination of flowing gas that may contain solid or liquid particulate matter. The stream comprises gaseous components and is for example exhaust of a lean burn engine, which may contain certain non-gaseous components such as liquid droplets, solid particulates and the like. The exhaust gas stream of a combustion engine typically further comprises combustion products (CO.sub.2 and H.sub.2O), products of incomplete combustion (carbon monoxide (CO) and hydrocarbons (HC)), oxides of nitrogen (NO.sub.x), combustible and/or carbonaceous particulate matter (soot), and unreacted oxygen and nitrogen. As used herein, the terms upstream and downstream refer to relative directions according to the flow of an engine exhaust gas stream from an engine towards a tailpipe, with the engine in an upstream location and the tailpipe and any pollution abatement articles, such as filters and catalysts being downstream from the engine. The inlet end of a substrate is synonymous with the upstream end or front end. The outlet end is synonymous with the downstream end or rear end. An upstream zone is upstream of a downstream zone. An upstream zone may be closer to the engine or manifold, and a downstreatn zone may be further away from the engine or manifold,

[0077] The term in fluid communication is used to refer to articles positioned on the same exhaust line, i.e., a common exhaust stream passes through articles that are in fluid communication with each other. Articles in fluid communication may be adjacent to each other in the exhaust line. Alternatively, articles in fluid communication may be separated by one or more articles, also referred to as washcoated monoliths. As used herein, the terms nitrogen oxides or NO.sub.x designate the oxides of nitrogen, such as, e.g., NO or NO.sub.2.

[0078] As used herein. impregnated or impregnation refers to permeation of the catalytic material into the porous structure of the support material.

[0079] As used herein, the term support or support material refers to any high surface area material, usually a metal oxide material, upon which a catalytic precious metal is applied. The term on a support means dispersed on, incorporated into, impregnated into, on, in, deposited on, or otherwise associated with.

[0080] As used herein, the term selective catalytic reduction (SCR) refers to the catalytic process of reducing oxides of nitrogen to dinitrogen (N.sub.2) using' a nitrogenous reductant.

[0081] As used herein, the term substrate refers to the monolithic material onto which the catalyst composition, that is, catalytic coating, is disposed, typically in the form of a. washcoat. In some embodiments, the substrates are flow-through monoliths and monolithic wall-flow filters. Flow-through and wall-flow substrates are taught, for example, in International Application Publication No. WO2016/070090, which is incorporated herein by reference. A washcoat is formed by preparing a slurry containing a specified solids content (e.g., 30-90% by weight) of catalyst in a liquid, which is then coated onto a substrate and dried to provide a washcoat layer. Reference to monolithic substrate means a unitary structure that is homogeneous and continuous from inlet to outlet. A washcoat is formed by preparing a slurry containing a certain solid content (e.g., 20%-90% by weight) of particles in a liquid vehicle, which is then coated. onto a substrate and dried to provide a washcoat layer.

[0082] The terms on and over in reference to a coating layer may be used synonymously herein. The term directly on means in direct contact with. The disclosed articles are referred to in certain embodiments as comprising one coating layer on a second coating layer, and such language is intended to encompass embodiments with intervening layers, where direct contact between the coating layers is not required (i.e., on is not equated with directly on).

[0083] As used herein, the term vehicle means, for instance, any vehicle having an internal combustion engine and includes, but is not limited to, passenger automobiles, sport utility vehicles, minivans, vans, trucks, buses, refuse vehicles, freight trucks, construction vehicles, heavy equipment, military vehicles, farm vehicles, and the like.

[0084] As used herein, the term washcoat has its usual meaning in the art of a thin, adherent coating of a catalytic or other material applied to a substrate material, such as a honeycomb-type carrier member, which is sufficiently porous to permit the passage of the gas stream being treated. The washcoat can optionally comprise a binder selected from silica, alumina, titania, zirconia, cerin, or a combination thereof. The loading of the binder is about 0.1 wt. % to 10 wt. %, based on the weight of the washcoat. As used herein and as described in Fleck, Ronald and Farrauto, Robert, Catalytic Air Pollution Control, New York: Wiley-Interscience, 2002, pp. 18-19, a washcoat layer includes a compositionally distinct layer of material disposed on the surface of a monolithic substrate or an underlying washcoat layer. A substrate can contain one or more washcoat layers, and each washcoat layer can be different in some way (e.g., may differ in physical properties thereof such as, for example, particle size or crystallite phase) and/or may differ in the chemical catalytic functions.

[0085] Unless otherwise indicated, all parts and percentages are by weight. Weight percent (wt %), if not otherwise indicated, is based on an entire composition free of any volatiles, that is, based on dry solids content.

[0086] All methods described herein can be perfortned in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., such as) provided herein, is intended merely to better illuminate the materials and methods and does not pose a limitation on the scope unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element is essential to the practice of the disclosed materials and methods.

[0087] All U.S. patent applications, published patent applications, and patents referred to herein are hereby incorporated by reference.

Non-Limiting Example Embodiments 1:

[0088] Without limitation, some non-limiting embodiments ofthe disclosure include:

1. An oxidation catalyst composition comprising: [0089] a platinum group metal (PGM) component comprising palladium, platinum, or a combination thereof; [0090] a manganese component; and [0091] a first refractory metal oxide support material comprising zirconia.
2. The oxidation catalyst composition of Embodiment 1, comprising manganese in an amount by weight, on an oxide basis, from about 0.1% to about 90% (e.g., about 1% to about 90%; about 1% to about 40%), based on the weight of the first refractory metal oxide support material.
3. The oxidation catalyst composition of Embodiment 1 or 2, wherein the manganese cotrrponent is deposited on the first refractory metal oxide support material.
4. The oxidation catalyst composition of any one of Embodiments 1-3, wherein the first refractory metal oxide support material comprises zirconia in an amount by weight from about 1% to about 99% (e.g., about 5% to about 99%).
5. The oxidation catalyst composition of any one of Embodiments 1-4 ; wherein the first refractory metal oxide support material further comprises alumina, silica; ceria, titanium oxide, silica-doped alumina, silica-titania, silica-zirconia, yttrium-zirconium, manganese-zirconium, tungsten-titanic, zirconia-titania, zirconia-ceria, zirconia-alumina, manganese-alumina, lanthanum-zirconia, lanthanum-zirconia-alumina, magnesium-alumina oxide, and combinations thereof.
6. The oxidation catalyst composition of any one of Embodiments 1-5, wherein the zirconia in the first refractory metal oxide support material is doped with lanthanum in an amount by weight from about 1% to about 40%, on an oxide basis, based on the weight of the zirconia.
7. The oxidation catalyst composition of any one of Embodiments 1-6, further comprising a base metal oxide chosen from oxides of cerium, iron, cobalt, zinc, chromium, molybdenum, nickel, tungsten, copper, magnesium, antimony, tin, lead, yttrium, and combinations thereof.
8. The oxidation catalyst composition of Embodiment 7, wherein the base metal oxide is supported on the first refractory metal oxide support material.
9. The oxidation catalyst composition of Embodiment 7 or 8, wherein: [0092] the base metal oxide is an oxide of ceria, and [0093] the ceria is present in an amount up to about 99% (e.g., up to about 50%) by weight, based on the weight of the first refractory metal oxide support material.
10. The oxidation catalyst composition of any one of Embodiments 1-9, comprising: [0094] manganese in an amount by weight, on an oxide basis, from about 1% to about 60% (e.g., about 1% to about 30%; about 5% to about 20%; about 5% to about 40%), based on the weight of the first refractory metal oxide support material; and [0095] ceria in an amount from about 1% to about 99% (e.g., about 1% to about 30%; about 1% to about 20%; about 1% to about 10%), by weight, based on the weight of the first refractory metal oxide support material.
11. The oxidation catalyst composition of any one of Embodiments 1-10, wherein: [0096] the palladium is loaded on the first refractory metal oxide support in an amount by weight from about 0% to about 10%, based on the weight of the first refractory metal oxide support; [0097] the platinum is loaded on the first refractory metal oxide support in an amount by weight from about 0% to about 10%, based on the weight of the first refractory metal oxide support; and [0098] wherein at least one of the platinum or the palladium is present in an amount by weight of about 0.1% or greater, based on the weight of the first refractory metal oxide support material.
12. The oxidation catalyst composition of any one of Embodiments 1-11, wherein the PGM component comprises a combination of platinum and palladium.
13. The oxidation catalyst composition of Embodiment 12, wherein a ratio of palladium to platinum by weight is from about 100 to about 0.01.
14. The oxidation catalyst composition of Embodiment 12, wherein a ratio of palladium to platinum by weight is from about 1 to about 0.01.
15. The oxidation catalyst composition of any one of Embodiments 1-14, further comprising a second refractory metal oxide support material.
16. The oxidation catalyst composition of Embodiment 15, wherein the second refractory metal oxide support material comprises alumina, silica, zirconia, titanic, ceria, silica-doped alumina, silica-titania, silica-zirconia, yttrium-zirconium, manganese-zirconium, tungsten-titania, zirconia-titanic, zirconia-ceria, zirconia-alumina, mannnese-alumina, lanthanum-zirconia, lanthanum-zirconia-alumina, magnestwn-alumina oxide, or a canibination thereof.
17. The oxidation catalyst composition of Embodiment 15 or 16, wherein the second refractory metal oxide support material comprises a base metal oxide chosen from oxides of cerium, iron, cobalt, zinc, chromium, molybdenum, nickel, tungsten, copper, magnesium, antimony, tin, lead, yttrium, and combinations thereof.
18. The oxidation catalyst composition of any one of Embodiments 15-17, wherein the PGM component is supported on the second refractory metal oxide support material in an amount by weight from about 0,1% to about 10% (e.g., about 0.5% to about 10%), based on the weight of the second refractory metal oxide support material.
19. The oxidation catalyst composition of any one of Embodiments 15-18, wherein the second refractory metal oxide support material comprises alumina or zirconia.
20. The oxidation catalyst composition of Embodiment 19, wherein the zirconia in the second refractory metal oxide support material is doped with lanthanum in an amount by weight from about 0.1% to about 40% (e.g., from about 1% to about 40%), on an oxide basis, based on the weilzht of the zirconia.
21. The oxidation catalyst composition of any one of Embodiments 15-49, wherein the second refractory metal oxide support material is substantially free of lanthanum.
22. The oxidation catalyst composition of any one of Embodiments 15-21, wherein the second refractory metal oxide support material comprises manganese.
23. The oxidation catalyst composition of any one of Embodiments 15-22, wherein the manganese component is supported on the first refractory metal oxide support material, and the PGM component is supported on the second refractory metal oxide support material.
24. The oxidation catalyst composition of Embodiment 23, wherein the PGM component is supported on the second refractory metal oxide support material in an amount from about to about 10% (e.g., about 0.5% to about 5%) by weight, based on the weight of the second refractory metal oxide support material.
25. The oxidation catalyst composition of Embodiment 15, wherein: [0099] the manganese component is manganese oxide, supported on the first refractory metal oxide support material in an amount by weight, on an oxide basis, from about 0.1% to about 40% (e.g., from about 1% to about 40%), based on the weight of the first refractory metal oxide support material; and [0100] the PGM component is supported on the second refractory metal oxide support material, wherein the second refractory metal oxide support material is chosen from alumina, silica-doped alumina, titania, titania-doped alumina, zirconium doped alumina zirconia, and zirconia doped with from about 1% to about 40% by weight of lanthana, based on the weight of the zirconia.
21. The oxidation catalyst composition of Embodiment 25, wherein the first refractory metal oxide support material further comprises ceria in an amount by weight from about 1% to about 50%, based on the weight of the first refractory metal oxide support material.
21. The oxidation catalyst composition of any one of Embodiments 1-25, wherein the oxidation catalyst composition is substantially free of copper.
28. A catalytic article comprising a substrate having an inlet end and an outlet end defining an overall length, and a catalytic coating disposed on at least a portion thereof, the catalytic coating comprising a first washcoat and a second washcoat, wherein: [0101] the first washcoat comprises a manganese component and a first refractory metal oxide support material comprising zirconia, wherein the manganese component is supported. on the first refractory metal oxide support material as manganese oxide or a mixed oxide; and [0102] the second washcoat comprises a platinum group metal (PGM) component comprising palladium, platinum, or a combination thereof, and a second refractory metal oxide support material, wherein the PGM component is supported on the second refractory metal oxide support material.
29. The catalytic article of Embodiment 28, comprising manganese in an amount by weight, on an oxide basis, from about 0.1% to about 40% (e.g., from about 1% to about 40%), based on the weight of the first refractory metal oxide support material.
30. The catalytic article of Embodiment 28 or 29, further comprising a base metal oxide supported on the first refractory metal oxide support material, wherein the base metal oxide is chosen from oxides of cerium, iron, cobalt, zinc, chromium, molybdenum, nickel, tungsten, copper, and combinations thereof.
31. The catalytic article of Embodiment 28 or 29, further comprising a base metal oxide supported on the first refractory metal oxide support material, wherein the base metal oxide is chosen from oxides of cerium, iron, cobalt, zinc, chromium, molybdenum, nickel, tungsten, magnesium, antimony, tin, lead, yttrium and combinations thereof.
32. The catalytic article of Embodiment 30, wherein the base metal oxide is an oxide of ceria, and wherein the ceria is present in an amount up to about 30% by weight, based on the weight of the first refractory metal oxide support material.
33. The catalytic article of Embodiment 32, comprising: [0103] manganese in an amount by weight, on an oxide basis, from about 1% to about 30%, based on the weight of the first refractory metal oxide support material; and [0104] ceria in an amount from about 1% to about 30%, based on the weight of the first refractory metal oxide support material.
34. The catalytic article of any one of Embodiments 28-33, wherein the zirconia in the first refractory metal oxide support material is doped with from about 1% to about 40% lanthanum oxide by weight, based on the total weight of the zirconia.
35. The catalytic article of any one of Embodiments 28-34, wherein the second refractory metal oxide support material comprises alumina, silica, zirconia, titania, ceria, or a combination thereof.
36. The catalytic article of any one of Embodiments 28-34, wherein the second refractory metal oxide support material comprises alumina.
37. The catalytic article of any one of Embodiments 28-34, wherein the second refractory metal oxide support material comprises zirconia.
38. The catalytic article of Embodiment 37, wherein the zirconia in the second refractory metal oxide support material is doped with trom about 1% to about 40% lanthanum oxide by weight, based on the total weight of the zirconia.
39. The catalytic article of any one of Embodiments 28-34, wherein the second refractory metal oxide support material is chosen from alumina, silica-doped alumina, titania, titania-doped alumina, zirconium doped alumina, zirconia, and zirconia doped with from about 1 to about 40% by weight of lanthana, based on the weight of the zirconia.
40. The catalytic article of any one of Embodiments 28-39, wherein the PGM component comprises a combination of platinum and palladium.
41. The catalytic article of Embodiment 40, wherein a ratio of palladium to platinum by weight is from about 100 to about 0.01.
42. The catalytic article of Embodiment 40, wherein a ratio of palladium to platinum by weight is from about 1 to about 0.01.
43. The catalytic article of any one of Embodiments 28-42, wherein the total PGM component loading on the catalytic article is from about 5 g/ft.sup.3 to about 200 g/ft.sup.3.
44. The catalytic article of any one of Embodiments 28-42, wherein the PGM is supported on the second refractory metal oxide support material in an amount from about 0.5% to about 10% (e.g., from about 0.5% to about 5%) by weight, based on the weight of the second refractory metal oxide support material.
45. The catalytic article of Embodiment 28, wherein: [0105] the manganese component is manganese oxide, supported on the first refractory metal oxide support material in an amount by weight, on an oxide basis, from about 1% to about 30%, based on the weight of the first refractory metal oxide support material, wherein the first refractory metal oxide support material comprises alumina or zirconia, wherein the zirconia is doped with from about 1% to about 40% lanthana, based on the weight of the zirconia; [0106] the first refractory metal oxide support material further comprises ceria in an amount by weight from about 1% to about 50%, based on the weight of the first refractory metal oxide support material; and [0107] the PGM component is supported on the second refractory metal oxide support material, wherein the second refractory metal oxide support material is chosen from alumina, silica-doped alumina, titania, titania-doped alumina, zirconium doped alumina, zirconia, and zirconia doped with from about 1% to about 40% by weight of lanthana, based on the weight of the zirconia.
46. The catalytic article of any one of Embodiments 28-45, wherein the first and second washcoats are substantially free of copper.
47. The catalytic article of any one of Embodiments 28-46, wherein the first washcoat is disposed directly on the substrate, and the second washcoat is disposed on at least a portion of the first washcoat.
48. The catalytic article of any one of Embodiments 28-46, wherein the second washcoat is disposed directly on the substrate, and the first washcoat is disposed on at least a portion of the second washcoat.
49. The catalytic article of any one of Embodiments 28-46, wherein the catalytic article has a zoned configuration, wherein the first washcoat is disposed directly on the substrate from the outlet end to a length from about 20% to about 100% of the overall length; and the second washcoat is disposed on the substrate from the inlet end to a length from about 20% to about 100% of the overall length.
50. The catalytic article of any one of Embodiments 28-46, wherein the catalytic article has a zoned configuration, wherein the second washcoat is disposed directly on the substrate from the outlet end to a length from about 20% to about 100% of the overall length; and the first washcoat is disposed on the substrate from the inlet end to a length from about 20% to about 100% of the overall length.
51. A catalytic article comprising a substrate having an inlet end and an outlet end defining an overall length, and a catalytic coating disposed on at least a portion thereof, the catalytic coating comprising a first washcoat, a second washcoat, and a third washcoat, wherein: [0108] the first washcoat comprises a manganese component and a first refractory metal oxide support material comprising zirconi a, wherein the manganese component is supported on the first refractory metal oxide support material as manganese oxide or a mixed oxide; [0109] the second washcoat comprises a base metal oxide component comprising ceria, manganese oxide, zirconia, lanthanum oxide, copper oxide, or a combination thereof, and a. second refractory metal oxide support material, wherein the base metal oxide component s supported on the second refractory metal oxide support material; and [0110] the third washcoat comprises a platinum group metal (PGM) component comprising palladium, platinum, or a combination thereof, and a third refractory metal oxide support material, wherein the PGM component is supported on the third refractory metal oxide support material.
52. The catalytic article of Embodiment 51, wherein the zirconia in the first refractory metal oxide support material is doped with about 1% to about 40% lanthanum oxide by weight, based on the total weight of the zirconia.
53. The catalytic article of Embodiment 51 or 52, wherein the second refractory metal oxide support material comprises alumina, silica, zirconia, titanic, ceria, silica-doped alumina, titania, titania-doped alumina, zirconium doped alumina, zirconia, silica-titania, silica-zirconia, yttrium-zirconium, manganese-zirconium, tungsten-titania, zirconia-titania, zirconia-ceria, zirconia-alumina, manganese-alumina, lanthanum-zirconia, lanthanum-zirconia-alumina, magnesium-alumina oxide, or a combination thereof.
54. The catalytic article of any one of Embodiments 51-53, wherein the second refractory metal oxide support material comprises alumina.

[0111] The catalytic article of any one of Embodiments 51-54, wherein the second refractory metal oxide support material comprises silica-doped alumina.

56. The catalytic article of any one of Embodiments 51-53, wherein the second refractory metal oxide support material comprises zirconia.
57. The catalytic article of Embodiment 56, wherein the zirconia in the second refractory metal oxide support material is doped with from about 0.1% to about 40% lanthanum oxide by weight, based on the total weight of the zirconia.
58. The catalytic article of any one of Embodiments 51-57, wherein the third refractory metal oxide support material comprises alumina, silica, zirconia, titania, ceria, silica-doped. alumina, titania, titania-doped alumina, zirconium doped alumina, zirconia, silica-titanic, silica-zirconia, tungsten-titania, zirconia-titania, zirconia-ceria, zirconia-alumina, lanthanum-zirconia, lanthanum-zirconia-alumina, magnesium-alumina oxide, or a combination thereof.
59. The catalytic article of any one of Embodiments 51-58, wherein the PGM component comprises a combination of platinum and palladium.
60. The catalytic article of any one of Embodiments 51-59, wherein the first washcoat is disposed directly on the substrate, and the second washcoat is disposed on at least a portion of the first washcoat.
61. The catalytic article of any one of Embodiments 51-59, wherein the second washcoat is disposed directly on the substrate, and the first washcoat is disposed on at least a portion of the second washcoat.
62. The catalytic article of any one of Embodiments 51-59, wherein the first washcoat is disposed directly on the substrate, the second washcoat is disposed on at least a portion of the first washcoat, and the third washcoat is disposed on at least a portion of the second washcoat.
63. The catalytic article of any one of Embodiments 51-59, wherein the third washcoat is disposed directly on the substrate, the second washcoat is disposed on at least a portion of the third washcoat, and the first washcoat is disposed on at least a portion of the second washcoat.
64. The catalytic article of any one of Embodiments 51-59, wherein the first washcoat is disposed directly on the substrate, the third washcoat is disposed on at least a portion of the first washcoat, and the second washcoat is disposed on at least a portion of the third washcoat.
65. The catalytic article of any one of Embodiments 51-59, wherein the second washcoat is disposed directly on the substrate, the third washcoat is disposed on at least a portion of the second washcoat, and the first washcoat is disposed on at least a portion of the third washcoat.
66. The catalytic article of any one of Embodiments 51-59, wherein the second washcoat is disposed directly on the substrate, the first washcoat is disposed on at least a portion of the second washcoat, and the third washcoat is disposed on at least a portion of the first washcoat.
67. The catalytic article of any one of Embodiments 51-59, wherein the catalytic article has a zoned configuration, wherein: [0112] the first washcoat is disposed directly on the substrate from the outlet end to a length from about 20% to about 100% of the overall length; [0113] the second washcoat is disposed on the substrate from the inlet end to a length from about 20% to about 100% of the overall length; and [0114] the third washcoat is disposed on the substrate from the inlet end to a length from about 20% to about 100% of the overall length.
68. An exhaust gas treatment system comprising the catalytic article of any one of Embodiments 28-67, wherein the catalytic article is downstream of and in fluid communication with a compression ignition internal combustion engine.
69. A method fix treating an exhaust gas stream comprising hydrocarbons and/or carbon monoxide and/or NO.sub.x, the method comprising contacting the exhaust gas stream with the catalytic article of any one of Embodiments 28-67, or the exhaust gas treatment system of Embodiment 68.
70. A formaldehyde oxidation catalyst composition comprising: [0115] a refractory metal oxide support material comprising zirconia; [0116] manganese in an amount by weight, on an oxide basis, from about 1% to about 30%, based on the weight of the refractory metal oxide support material; and [0117] ceria in an amount from about 0% to about 30%, based on the weight of the refractory metal oxide support material, [0118] wherein the formaldehyde oxidation catalyst composition is substantially free of copper.
71. The formaldehyde oxidation catalyst composition of Embodiment 70, wherein the manganese is disposed on the refractory metal oxide support material.
72. The formaldehyde oxidation catalyst composition of Embodiment 70, wherein the ceria is disposed on the refractory metal oxide support material,
73. The catalytic article of Embodiment 70, wherein the zirconia in the refractory metal oxide support material is doped with from about 0.1% to about 40% lanthanum oxide by weight, based on the total weight of the zirconia.

Non-Limiting Example Embodiments 2

[0119] Without limitation, some non-limiting embodiments/clauses of the disclosure include:

1. An oxidation catalyst composition for use in an exhaust gas treatment system comprising a compression ignition internal combustion engine, the composition comprising: [0120] a platinum group metal (PGM) component comprising palladium, platinum, or a combination thereof; [0121] a manganese component; and [0122] a first refractory metal oxide support material comprising zirconia, and [0123] an optional second refractory metal oxide support material
2. The oxidation catalyst composition of Clause 1, comprising manganese in an amount by weight, on an oxide basis, from about 1 to about 40%, based on the weight of the first refractory metal oxide support material.
3. The oxidation catalyst composition of Clause 1, wherein the first refractory metal oxide support material comprises zirconia in an amount by weight from about 5% to about 99%.
4. The oxidation catalyst composition of Clause 1, wherein the zirconia is doped with lanthanum in an amount by weight from about 1 to about 40% on an oxide basis, based on the weight of the zirconia.
5. The oxidation catalyst composition of Clause 1, further comprising a base metal oxide, the base metal selected from the group consisting of cerium, iron, cobalt, zinc, chromium, molybdenum, nickel, tungsten, copper, and combinations thereof.
6. The oxidation catalyst composition of Clause 5, wherein the base metal is selected. from the group consisting of cerium, iron, cobalt, zinc, chromium, molybdenum, nickel, tungsten, and combinations thereof.
7. The oxidation catalyst composition of Clause 5, wherein the base metal oxide is ceria, and wherein the ceria is present in an amount up to about 50% by weight, based on the weight of the first refractory metal oxide support material.
8. The oxidation catalyst composition of Clause 1, comprising: [0124] manganese in an amount by weight, on an oxide basis, from about 1 to about 30%, or from about 5 to about 20%, based on the weight of the first refractory metal oxide support material; and [0125] ceria in an amount from about 1 to about 30, from about 1 to about 20, or from about 1 to about 10% by weight, based on the weight of the first refractory metal oxide support material.
9. The oxidation catalyst composition of Clause 1, wherein: [0126] the palladium is loaded on the first refractory metal oxide support in an amount by weight from 0% to 10%, based on the weight of the first refractory metal oxide support; [0127] the platinum is loaded on the first refractory metal oxide support in an amount by weight from 0% to 10%, based on the weight of the first refractory metal oxide support; and [0128] wherein at least one of the platinum or the palladium is present in an amount by weight of about 0.1% or greater, based on the weight of the first refractory metal oxide support.
10. The oxidation catalyst composition of Clause 1, wherein the PGM component comprises a combination of platinum and palladium.
11. The oxidation catalyst composition of Clause 9, wherein a ratio of palladium to platinum by weight is from about 100 to about 0.05.
12. The oxidation catalyst composition of Clause 9, wherein a ratio of palladium to platinum by weight is from about 1 to about 0.05, or from about 0.5 to about 0.1.
13. The oxidation catalyst composition of Clause 1, further comprising a second refractory metal oxide support material.
14, The oxidation catalyst composition of Clause 13, wherein the second refractory metal oxide support material comprises alumina, silica, zirconia, titania, ceria, or a combination thereof.

[0129] The oxidation catalyst composition of Clause 13, wherein the second refractory metal oxide support material comprises alumina.

16. The oxidation catalyst composition of Clause 13, wherein the PGM component is supported on the second refractory metal oxide support material in an amount by weight from about 0.5 to about 10%, based on the weight of the second refractory metal oxide support material.
17. The oxidation catalyst composition of Clause 13, wherein the second refractory metal oxide support material comprises zirconia.
18. The oxidation catalyst composition of Clause 17, wherein the zirconia is doped with lanthanum in an amount by weight from about 1 to about 40% on an oxide basis, based on the weight of the zirconia.
19. The oxidation catalyst composition of Clause 13, wherein the manganese component is supported on the first refractory metal oxide support material, and the PGM component is supported on the second refractory metal oxide support material.
20. The oxidation catalyst composition of Clause 19, wherein the PGM component is supported on the second refractory metal oxide support material in an amount from about 0.5 to about 5% by weight, based on the weight of the second refractor metal oxide support material
21. The oxidation catalyst composition of Clause 1, wherein: [0130] the manganese component is manganese oxide, supported on the first refractory metal oxide support material in an amount by weight, on an oxide basis, from about 1 to about 40%, based on the weight of the first refractory metal oxide support material, wherein the first refractory metal oxide support material comprises zirconia; and [0131] the PGM component is supported on the second refractory metal oxide support material, wherein the second refractory metal oxide support material is selected from the group consisting of alumina, silica-doped alumina, titania, titania-doped alumina, zirconium doped alumina, zirconia, and zirconia doped with from about 1 to about 40% by weight of lanthana, based on the weight of the zirconia.
22. The oxidation catalyst composition of Clause 21, wherein the zirconia is doped with from about 1 to about 40% lanthana, based on the weight of the zirconia.
23. The oxidation catalyst composition of Clause 21, wherein the first refractory metal oxide support material further comprises ceria in an amount by weight from about 1 to about 50%, based on the weight of the first refractory metal oxide support material.
24. The oxidation catalyst composition of any of Clauses 1-23, wherein the oxidation catalyst cornposition is substantially free of copper.
25. A catalytic article comprising a substrate having an inlet end and an outlet end defining an overall length, and a catalytic coating disposed on at least a portion thereof, the catalytic coating comprising a first and a second washcoat, wherein: [0132] the first washcoat comprises a manganese component and a first refractory metal oxide support material comprising zirconi a, wherein the manganese component is supported on the first refractory metal oxide support material as manganese oxide or a mixed oxide; and [0133] the second washcoat comprises a platinum group metal (PGM) component comprising palladium, platinum, or a combination thereof, and a second refractory metal oxide support material, wherein the PGM component is supported on the second refractory metal oxide support material.
26. The catalytic article of Clause 25, comprising manganese in an amount by weight, on an oxide basis, from about 1 to about 40%, based on the weight of the first refractory metal oxide support material.
27. The catalytic article of Clause 25, further comprising a base metal oxide supported on the first refractory metal oxide support material, the base metal selected from the group consisting of cerium, iron, cobalt, zinc, chromium, molybdenum, nickel, tungsten, copper, and combinations thereof.
28. The catalytic article of Clause 27, wherein the base metal is selected from the group consisting of cerium, iron, cobalt, zinc, chromium, molybdenum, nickel, tungsten, and combinations thereof.
29. The catalytic article of Clause 27, wherein the base metal oxide is ceria, and wherein the ceria is present in an amount up to about 30% by weight, based on the weight of the first refractory metal oxide support material.
30. The catalytic article of Clause 25, comprising: [0134] manganese in an amount by weight, on an oxide basis, from about 1 to about 30%, or from about 5 to about 20%, based on the weight of the first refractory metal oxide support material; and [0135] ceria in an amount from about 1 to about 30, from about 1 to about 20, or from about 1 to about 10% by weight, based on the weight of the first refractory metal oxide support material.
31. The catalytic article of Clause 25, wherein the zirconia is doped with from about 1 to about 40% lanthanum oxide by weight, based on the total weight of the zirconia.
32. The catalytic article of Clause 25, wherein the second refractory metal oxide support material comprises alumina, silica, zirconia, titania, coria, or a combination thereof.
33. The catalytic article of Clause 32, wherein the second refractory metal oxide support material comprises alumina.
34. The catalytic article of Clause 32, wherein the second refractory metal oxide support material comprises zirconia.
35. The catalytic article of Clause 34, wherein the zirconia is doped with from about 1 to about 40% lanthanum oxide by weight, based on the total weight of the zirconia.
36. The catalytic article of Clause 32, wherein the second refractory metal oxide support material is selected from the group consisting of alumina, silica-doped alumina, titania, titania-doped alumina, zirconium doped alumina, zirconia, and zirconia doped with from about 1 to about 40% by weight of lanthana, based on the weight of the zirconia.
37. The catalytic article of Clause 25, wherein the PGM component comprises a combination of platinum and palladium.
38. The catalytic article of Clause 37, wherein a ratio of palladium to platinum by weight is from about 100 to about 0.05.
39. The catalytic article of Clause 37, wherein a ratio of palladium to platinum by weight is from about 1 to about 0.05, or from about 0.5 to about 0.1.
40. The catalytic article of Clause 37, wherein the total PGM component loading on the catalytic article is from about 5 g/ft.sup.3 to about 200 g/ft.sup.3.
41. The catalytic article of Clause 25, wherein the PGM is supported on the second refractory metal oxide support material in an amount from about 0.5 to about 5% by weight, based on the weight of the second refractory metal oxide support material.
42, The catalytic article of Clause 25, wherein: [0136] the manganese component is manganese oxide, supported on the first refractory metal oxide support material in an amount by weight, on an oxide basis, from about 1 to about 30%, based on the weight of the first refractory metal oxide support material, wherein the first refractory metal oxide support material comprises alumina or comprises zirconia. doped with from about 1 to about 40% lanthana, based on the weight of the zirconia [0137] the first refractory metal oxide support material further comprises coria in an amount by weight from about 1 to about 50%, based on the weight of the first refractory metal oxide support material; and [0138] the PGM component is supported on the second refractory metal oxide support material, wherein the second refractory metal oxide support material is selected from the group consisting of alumina, silica-doped alumina, titania, titania-doped alumina, zirconium doped alumina, zirconia, and zirconia doped with from about 1 to about 40% by weight of lanthana, based on the weight of the zirconia.
43. The catalytic article of any of Clauses 25-42, wherein the first and second washcoats are substantially free of copper.
44. The catalytic article of any one of Clauses 25 to 42, wherein the first washcoat is disposed directly on the substrate, and the second washcoat is on at least a portion of the first washcoat.
45. The catalytic article of any one of Clauses 25 to 42, wherein the second washcoat is disposed directly on the substrate, and the first washcoat is on at least a portion of the second washcoat.
46. The catalytic article of any one of Clauses 25 to 42, having a zoned configuration, wherein the first washcoat is disposed directly on the substrate from the outlet end to a length from about 20% to about 100% of the overall length; and the second washcoat is disposed on the substrate from the inlet end to a length from about 20% to about 100% of the overall length.
47. The catalytic article of any one of Clauses 25 to 42, having a zoned configuration, wherein the second washcoat is disposed directly on the substrate from the outlet end to a length from about 20% to about 100% of the overall length; and the first washcoat is disposed on the substrate from the inlet end to a length from about 20% to about 100% of the overall length.
48. An exhaust gas treatment system comprising the catalytic article of any one of Clauses 25 to 47, wherein the catalytic article is downstream of and in fluid communication with a compression ignition internal combustion engine.
49. A method for treating an exhaust gas stream comprising hydrocarbons and/or carbon monoxide and/or NOR, the method comprising contacting the exhaust gas stream with the catalytic article of any one of Clauses 25 to 47, or the exhaust gas treatment system of Clause 48.

Oxidation Catalyst Composition

[0139] As described herein above, the disclosure generally provides an oxidation catalyst composition comprising a refractory metal oxide support material, a platinwn group metal (PGM) component, and a manganese component. Each of the individual components of the composition are described further herein below.

Refractory Metal Oxide Support

[0140] The oxidation catalyst composition as disclosed herein comprises a refractory metal oxide support material. As used herein, refractory metal oxide refers to porous metal-containing oxide materials exhibiting chemical and physical stability at high temperatures, such as the temperatures associated with diesel engine exhaust. Exemplary refractory metal oxides include, but are not limited to, alumina, silica, zirconia, titania, cerin, and physical mixtures or chemical combinations thereof, including atomically-doped combinations and including high surface area or activated compounds such as activated alumina, in some embodiments, the refractory metal oxide support comprises alumina, silica, ceria, titanium oxide, silica-doped alumina, silica-titania, silica-zirconia, yttrium-zirconium, manganese-zirconium, tungsten-titania, zirconia-titania, zirconia-ceria, zirconia-alumina, manganese-alumina, lanthanum-zirconia, lanthanum-zirconia-alumina, magnesium-alumina oxide, and combinations thereof. Exemplary aluminas include large pore boehmite, gamma-alumina, and delta/theta alumina, Useful commercial aluminas include activated aluminas, such as high bulk density gamma-alumina, low or medium bulk density large pore gamma-alumina, and low bulk density large pore boehmite and gamma-alumina.

[0141] High surface area refractory oxide supports, such as alumina support materials, also referred to as gamma alumina or activated alumina, typically exhibit a BET surface area in excess of 60 m.sup.2/g, often up to about 200 m.sup.2/g or higher. Such activated alumina is usually a mixture of the gamma and delta phases of alumina, but may also contain substantial amounts of eta, kappa and theta alumina phases. As used herein, BET surface area has its usual meaning of referring to the Brunauer, Emmett, Teller method for determining surface area by N.sub.2 adsorption. In some embodiments, the refractory metal oxide support material (e.g., activated alumina) has a specific surface area of 60 m.sup.2/g to 350 m.sup.2/g, for example, from about 90 m.sup.2/g to about 250 m.sup.2/g.

[0142] In some embodiments, the refractory metal oxide support material comprises alumina (Al.sub.2O.sub.3), silica (SiO.sub.2), zirconia (ZrO.sub.2), titania (TiO.sub.2), ceria (CeO.sub.2), or physical mixtures or chemical combinations thereof. In certain embodiments, refractory metal oxide supports useful in the oxidation catalyst composition disclosed herein are doped with another metal oxide, including, but not limited to, silica (SiO.sub.2), ceria (CeO.sub.2), titania (TiO.sub.2), or lanthana (La.sub.2O.sub.3). In some embodiments, the refractory metal oxide support is selected from doped materials, such as Si-doped alumina materials (including, but not limited to 1-10% SiO.sub.2-Al.sub.2O.sub.3), doped titania materials, such as Si-doped titania materials (including, but not limited to, 1-10% SiO.sub.2TiO.sub.2) or doped zirconia materials, such as Si-doped ZrO.sub.2 (including, but not limited to, 5-30% SiO.sub.2ZrO.sub.2). Accordingly, in some embodiments, the refractory metal oxide support material comprises SiO.sub.2-doped Al.sub.2O.sub.3, SiO.sub.2-doped TiO.sub.2, or SiO.sub.2-doped ZrO.sub.2 (including, but not limited to 5-30% SiO.sub.2ZrO.sub.2).

[0143] In some embodiments, the refractory metal oxide support material comprises zirconia. In some embodiments, the zirconia is doped with one or more dopants. In some embodiments, the refractory metal oxide support material comprises zirconia in an amount of from about 5% to about 99% (i.e., the total amount of dopants present is from about 1 to about 95%). In some embodiments, the refractory metal oxide support material comprises zirconia in an amount of from about 20% to about 99% (i.e., the total amount of dopants present is from about 1% to about 80%). In some embodiments, the zirconia is doped with lanthana. In some embodiments, the refractory metal oxide support material comprises zirconia doped with from about 1% to about 40% La203. In some embodiments, the zirconia is doped with from about 1%, about 2%, about 3%, about 4%, about 5%, about 6%, about 7%, about 8%, about 9%, or about 10%, to about 15%, about 20%, about 25%. about 30%, about 35%, or about 40% lanthana by weight, based on the weight of the zirconia. In some embodiments, the zirconia is doped with from about 1% to about 10% lanthana. In some embodiments, the zirconia is doped with about 9% lanthana.

[0144] The dopant metal oxide(s) can be introduced using, for example, an incipient wetness impregnation technique. In some embodiments, the metal oxide may be present in the doped refractory metal oxide support material in the form of a mixed oxide, meaning the metal oxides are covalently bound with one another through shared oxygen atoms,

[0145] The oxidation catalyst composition may comprise any of the above named refractory metal oxides and in any amount. For example, refractory metal oxides in the catalyst composition may comprise from about 15 wt %, about 20 wt %, about 25 wt %, about 30 wt %, about 35 wt %, about 40%, about 45%, or about 50 wt %, to about 55 wt %, about 60 wt %, about 65 wV/0, about 70 wt %, about 75 wt %, about 80 wt %, about 85 wt %, about 90 wt %, about 95 wt %, or about 99 wt %, based on the total dry weight of the catalyst composition.

[0146] Reference is made herein to a first refractory metal oxide support material, and in some embodiments, a second refractory metal oxide support material, so as to distinguish each refractory metal oxide support material. The first and second refractory metal oxide support materials may be the same or different. In some embodiments, the first and second refractory metal oxide support material are the same. In other embodiments, the first and second refractory metal oxide support materials are different.

[0147] In some embodiments, the first refractory metal oxide support material comprises zirconia. In some embodiments, the first refractory metal oxide support comprises zirconia doped with lanthanum oxide. In some embodiments, the first refractory metal oxide support material comprises zirconia doped with from 1-40% lanthanum oxide. In some embodiments, the first refractory metal oxide support material comprises zirconia doped with from 1-10% lanthanum oxide. In some embodiments, the first refractory metal oxide support material comprises zirconia doped with about 9% lanthanum oxide.

[0148] In some embodiments, the first refractory metal oxide support material is substantially free of lanthanum.

[0149] In some embodiments, the second refractory metal oxide support material comprises manganese.

[0150] In some embodiments, the second refractory metal oxide support material comprises alumina, silica, zirconia, tetania, ceria, silica-doped alumina, silica-titania, silica-zirconia, yttrium-zirconium, manganese-zirconium, tungsten-titania, zirconia-titania, zirconia-ceria, zirconia-alumina, manganese-alumina, lanthanum-zirconia, lanthanum-zirconia.-alumina, magnesium-alumina oxide, or a combination thereof. In some embodiments, the second refractory metal oxide support material comprises alumina, silica, zirconia, titania, ceria, or a combination thereof In one or more embodiments, the second refractory metal oxide support is chosen from (e.g., selected from the group consisting of) gamma alumina, silica doped alumina, ceria doped alumina, and titania doped alumina. In some embodiments, the second refractory metal oxide support material is chosen from (e.g., selected from the group consisting of) altunina, silica-doped alumina, titania, titania-doped alumina, zirconium doped alumina, zirconia, and zirconia doped with from about 1% to about 40% by weight of lanthana, based on the weight of the zirconia. In some embodiments, the second refractory metal oxide support material is chosen from (e.g., selected from the group consisting of) gamma alumina and alumina doped with from about 1% to about 0% by weight of SiO.sub.2. In some embodiments, the second refractory metal oxide support material is alumina doped with from about 1% to about 10% by weight of SiO.sub.2, for example, about 1%, about 2%, about 3%, about 4%, about 5%, about 6%, about 7%, about 8%, about 9%, or about 10% by weight of SiO.sub.2. In some embodiments, the second refractory metal oxide support material is alumina.

[0151] In some embodiments, the second refractory metal oxide support material comprises zirconia. In some embodiments, the second refractory metal oxide support material is chosen from (e.g., selected from the group consisting of) alumina, silica-doped alumina, zirconia, and zirconia doped with from about 1% to about 40% by weight of larithana, based on the weight of the zirconia. In some embodiments, the second refractory metal oxide support is zirconia doped with lanthanum oxide. In some embodiments, the second refractory metal oxide support material is zirconia doped with from 1-40% lanthanum oxide. In some embodiments, the second refractory metal oxide support material is zirconia doped with from 1-10% lanthanum oxide. In some embodiments, the second refractory metal oxide support material is zirconia doped with about 9% lanthanum oxide. In some embodiments, the first and second refractory metal oxide support material both comprise zirconia doped with from about 1-10% lanthanum oxide. In some embodiments, the first refractory metal oxide support material comprises zirconia doped with from about 1-10% lanthanum oxide, and the second refractory metal oxide support material is alumina.

[0152] In some embodiments, the second refractory metal oxide support material is substantially free of lanthanum.

Platinum Group Metal (PGM) Component

[0153] The oxidation catalyst composition as described herein comprises a platinum group metal (PGM) component. PGMs include platinum (Pt), palladium (Pd), ruthenium (Ru), rhodium (Rh), osmiwn (Os), iridium (Ir), gold (Au), and mixtures thereof. The PGM component can include the PGM in any valence state. As used herein, the term PGM component refers both to a catalytically active form of the respective PGM, as well as the corresponding PGM compound, complex, or the like which, upon calcination or use of the catalyst, decomposes or otherwise converts to the catalytically active form, usually the metal or the metal oxide. The PGM may be in metallic form, with zero valence (PGM(0)), or the PGM may be in an oxide form (e.g., including, but not limited to, platinum or an oxide thereof). The amount of PGM(0) present can be determined using ultrafiltration, followed by Inductively Coupled Plasma/Optical Emission Spectrometry (ICP-OES), or by X-Ray photoelectron spectroscopy (XPS).

[0154] In some embodiments, the PGM component comprises platinum, palladium, or a combination thereof. In some embodiments, the PGM component is palladium. In some embodiments, the PGM component is platinum In some embodiments, the PGM component is a combination of palladium and platinum. Exemplary weight ratios for such Pd/Pt combinations include, but are not limited to, weight ratios of from about 100 to about 0.01 Pd:Pt, for example, about 100:1, about 50:1, about 40:1, 30:1, about 25:1, about 20:1, about about 10:1, about 5:1, about 4:1, about 3:1, about 2:1, about 1:1, about 1:2, about 1:5, about 1:10, or about 1:20 Pd/Pt. In some embodiments, the PdtPt weight ratio is about 100. In some embodiments, the ratio of palladium to platinum by weight is from about 1 to about from about 1 to about 0.05, or from about 0.5 to about 0.1. In each case, the weight ratio is on an elemental (metal) basis.

[0155] The PGM component is supported (e.g., impregnated) on a refractory metal oxide support material as described herein above. The PGM component may be present in an amount in the range of about 0.01% to about 20% (e.g., about 0.1% to about 0%; about to about 5%) by weight on a metal basis, based on the total weight of the refractory metal oxide support material including the supported PGM. The oxidation catalyst composition may comprise the PGM, for example, Pd or Pt/Pd at from about 0.1 wt %, about 0.5 wt %, about 1.0 wt %, about 1.5 wt % or about 2.0 wt %, to about 3 wt %, about 5 wt %, about 7 wt %, about 9 wt %, about 10 wt %. about 12 wt %, about 15 wt %, about 16 wt %, about 17 wt %, about 18 wt %, about 19 wt %, or about 20 wt %, based on the total weight of the refractory metal oxide support material, including the supported PGM.

[0156] In some embodiments, the platinum group metal component is supported on the second refractory metal oxide support material. In some embodiments, the PGM component is platinum, palladium, or a combination thereof, and the PGM is supported on the second refractory metal oxide support material in an amount from about 0.5 to about 5% by weight, based on the weight of the second refractory metal oxide support material. In some embodiments, the PGM is supported on the second refractory metal oxide support material in an amount of about 2% by weight, based on the weight of the second refractory metal oxide support material.

[0157] In some embodiments, the total PGM component loading on the catalytic article is from about 5 g/ft.sup.3 to about 200 g/ft.sup.3.

Manganese Component

[0158] In some embodiments, an oxidation catalyst composition as described herein comprises a manganese component. As used herein, reference to a manganese component is intended to include Mn in various oxidation states, salts, and physical forms, generally as an oxide. Reference herein to a supported manganese component means that the manganese component is disposed in or on a refractory metal oxide support material through association, dispersion, impregnation, or other suitable methods, and may reside on the surface or be distributed throughout the refractory metal oxide support material. In some embodiments, the manganese component is derived from a soluble Mn species, including, but not limited to, Mn salts, such as an acetate salt, nitrate salt, sulfate salt, or a combination thereof. It will be appreciated by one of skill in the art, that upon calcination, the Mn species (e.g., a Mn salt) will become one or more forms of manganese oxide (Mn.sub.xO.sub.y wherein x is 1 or 2, and y is 1, 2, or 3). In some embodiments, the manganese component is MnO.sub.2, Mn.sub.2O.sub.3, Mn.sub.3O.sub.4, or combinations thereof.

[0159] According to some embodiments, a refractory metal oxide support is impregnated with a Mn salt. As used herein, the term impregnated means that a solution containing a Mn species is put into pores of a material such as a refractory metal oxide support. In some embodiments, impregnation of Mn is achieved by incipient wetness, where a volume of a diluted solution containing an Mn species is approximately equal to the pore volume of the support bodies. Incipient wetness impregnation generally leads to a substantially uniform distribution of the solution of the precursor throughout the pore system of the material. Alternative methods of adding metals such as Mn are also known in the art and can be used.

[0160] Thus, according to some embodiments, a refractory metal oxide support is treated with a source of Mn (e.g., a solution of a Mn salt) dropwise, in a planetary mixer, to impregnate the support with the Mn component. In some embodiments, a refractory metal oxide support containing the Mn component can be obtained from commercial sources.

[0161] In some embodiments, the manganese can be supported on the refractory oxide support by co-precipitating a Mn species (e.g., a Mn salt) and a refractory metal oxide support precursor, and then calcining the co-precipitated material so that the refractory oxide support material and the manganese are in solid solution together. Thus, according to some embodiments, mixed oxides containing oxides of manganese, aluminum, cerium, silicon, zirconium, or titanium can be formed.

[0162] The manganese component may be present in the refractory metal oxide support material over a range of concentrations. In some embodiments, the Mn content is in the ramie of about 1% to about 40% (including 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, or 40%) by weight, based on the weight of the refractory metal oxide support and calculated as the metal oxide. In some embodiments, the Mn content is in the range of 5% to 15% by weight, or about 8% to 12% by weight, based on the weight of the refractory metal oxide support. In some embodiments, the composition comprises manganese in an amount by weight, on an oxide basis, from about 1% to about 30%, from about 5% to about 20%, or from about 1% to about 10%, based on the weight of the refractory metal oxide support material. In some embodiments, the manganese component is supported on the first refractory metal oxide support material.

Base Meta/Oxide

[0163] In some embodiments, an oxidation catalyst composition as disclosed herein further comprises a base metal oxide. As used herein, base metal oxide refers to an oxide compound comprising a transition metal or lanthanide series metal that is catalytically active for oxidation of one or more exhaust gas components. For ease of reference herein, concentrations of base metal oxide materials are reported in terms of elemental metal concentration rather than the oxide form. Generally, at least a portion of the base metal oxide is disposed on or in the refractory metal oxide support. These oxides may include various oxidation states of the metal, such as monoxide, dioxide, trioxide, tetroxide, and the like, depending on the valence of the particular metal.

[0164] Suitable base metals include, but are not limited to, cerium, iron, cobalt, zinc, chromium, nickel, tungsten, copper, molybdenum, or combinations thereof In some embodiments, the base metal is chosen from (e.g., selected from the group consisting of) cerium, copper, iron, cobalt, zinc, chromium, nickel, tungsten, molybdenwn, and combinations thereof. In some embodiments, the base metal is chosen from (e.g., selected from the group consisting of) cerium, iron, cobalt, zinc, chromium, nickel, tungsten, molybdenum, and combinations thereof In some embodiments, the base metal is chosen from (e.g., selected from the group consisting of) cerium, copper, and a combination thereof. In some embodiments, the base metal is chosen from cerium, iron, cobalt, zinc, chromium, molybdenum, nickel, tungsten, magnesium, antimony, tin, lead, yttrium, manganese, and combinations thereof.

[0165] In some embodiments, the oxidation catalyst composition is substantially free of copper. By substantially free of copper is meant that no copper has been intentionally added, and only trace amounts may be present as impurities, for example, less than 0.1%, less than 0.01%, less than 0.001%, or even 0% by weight.

[0166] The concentration of any individual base metal oxide can vary, but will typically be from about 1 wt % to about 50 wt % relative to the weight of the refractory metal oxide support material on which it is supported (e.g., about 1% to about 50%, about 1% to about 30%, or about 5% to about 20% by weight, relative to the weight of the refractory metal oxide support). In some embodiments, the concentration of any individual base metal oxide is from about 1%, about 2%, about 3%, about 4%, about 5%, about 6%, about 7%, about 8%, about 9%, or about 10%, to about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, or about 50% by weight, based on the weight of the refractory oxide support material.

[0167] In some embodiments, the base metal oxide is supported on the first refractory metal oxide support material. In some embodiments, the base metal oxide is ceria. In some embodiments, the coria is present in an amount up to about 50% by weight, based on the weight of the first refractory metal oxide support material. In some embodiments, the ceria is present in an amount from about 1% to about 10%, from about 5% to about 20%, from about 10% to about 30%, or from about 20 to about 50% by weight, based on the weight of the first refractory metal oxide support material.

Preparation of the Oxidation Catalyst Composition,

[0168] The disclosed oxidation catalyst composition may, in some embodiments, be prepared via an incipient wetness impregnation method. Incipient wetness impregnation techniques, also called capillary impregnation, or dry impregnation are commonly used for the synthesis of heterogeneous materials, i.e., catalysts. Typically, a metal precursor (e.g., a PGM, manganese, or base metal oxide precursor) is dissolved in an aqueous or organic solution and then the metal-containing solution is added to a refractory metal oxide support containing the same pore volume as the volume of the solution that was added. Capillary action draws the solution into the pores of the support. Solution added in excess of the support pore volume causes the solution transport to change from a capillary action process to a diffusion process, which is much slower. The catalyst can then be dried and calcined to remove the volatile components within the solution, depositing the metal on the surface of the catalyst support. The maximum loading is limited by the solubility of the precursor in the solution. The concentration profile of the impregnated material depends on the mass transfer conditions within the pores during impregnation and drying. One of skill in the art will recognize other methods for loading the various components (e.g., PGM, manganese, or base metal) into the supports of the present compositions, for example, adsorption, precipitation, and the like.

[0169] During the subsequent calcination steps, or at least during the initial phase of use of the composition, the metal precursor compounds are converted into a catalytically active form of the metal or a compound thereof Non-limiting examples of suitable PGM precursors include palladium nitrate, toraammine palladium nitrate, tetraammine platinum acetate, and platinum nitrate. Non-limiting examples of suitable base metal oxide precursors are nitrates, acetates, or other soluble salts of, e.g., cerium, manganese, copper, and the like. A suitable method of preparing an oxidation catalyst composition is to prepare a mixture of a solution of a desired PGM compound (e.g., a platinum compound and/or a palladium compound) and at least one support, such as a finely divided, high surface area, refractory metal oxide support, e.g., lanthana-doped zirconia, which is sufficiently dry to absorb substantially all of the solution to fbrm a wet solid which is later combined with water to fbrm a coatable slurry. In some embodiments, the slurry is acidic, having, for example, a pH of about 2 to less than about 7. The pH of the slurry may be lowered by the addition of an adequate amount of an inorganic acid or an organic acid to the slurry. Combinations of both can be used when compatibility of acid and raw materials is considered. Example inorganic acids include, but are not limited to, nitric acid, Example organic acids include, but are not limited to, acetic, propionic, malonic, succinic, glutamic, adipic, maleic, furnaric, phthalic, tartaric, citric acid and the like. The impregnated refractory metal oxide support material is then dried and calcined as described above.

[0170] The wet impreunation method described above can similarly be used to introduce the manganese component, the base metal, or both into the refractory metal oxide support material. The impregnations can be conducted in a step-wise (sequential) fashion or in various combinations.

Formaldehyde Oxidation Catalyst Composition

[0171] Some embodiments of this disclosure relate to a formaldehyde oxidation catalyst composition comprising: [0172] a refractory metal oxide support material comprising zirconia; [0173] manganese in an amount by weight, on an oxide basis, from about 1% to about 30% (e.g., about 10%), based on the weight of the refractory metal oxide support material; and [0174] ceria in an amount from about 0% to about 30% (e.g., 0%; 10%), based on the weight of the refractory metal oxide support material, [0175] wherein the formaldehyde oxidation catalyst composition is substantially free of copper.

[0176] In some embodiments, the refractory metal oxide support material further comprises alumina, silica, ceria., titanium oxide, silica-doped alumina, silica-titanic, silica-zirconia, yttrium-zirconium, manganese-zirconium, tungsten-titania, zirconia-titania, zirconia-ceria, zirconia-alumina, manganese-alumina, lanthanwn-zirconia, lanthanum-zirconia-alumina, magnesium-alumina oxide, and combinations thereof.

[0177] In some embodiments, the manganese is disposed on the refractory metal oxide support material. In some embodiments, the ceria is disposed on the refractory metal oxide support material. In some embodiments, the manganese and the ceria are disposed on the refractory metal oxide support material.

[0178] In some embodiments, the zirconia in the refractory metal oxide support material is doped with from about 1% to about 40% (e.g., about 9%) lanthanum oxide by weight, based on the total weight of the zirconia.

Catalytic Articles

[0179] In one aspect is provided an oxidation catalyst article comprising the oxidation catalyst composition as disclosed herein. The article comprises a substrate having disposed on at least a portion thereof the oxidation catalyst composition as disclosed herein. Suitable substrates are described herein below.

Substrates

[0180] In some embodiments, the present oxidation catalyst composition is disposed on a substrate to form a catalytic article. Catalytic articles comprising the substrates are generally employed as part of an exhaust gas treatment system (e.g., catalyst articles including, but not limited to, articles including the oxidation catalyst composition disclosed herein). Useful substrates are 3-dimensional, having a length and a diameter and a volume, similar to a cylinder. The shape does not necessarily have to conform to a cylinder. The length is an axial length defined by an inlet end and an outlet end.

[0181] In some embodiments, the substrate for the disclosed composition(s) may be constructed of any material typically used for preparing automotive catalysts and will typically comprise a metal or ceramic honeycomb structure. The substrate typically provides a plurality of wall surfaces upon which the washcoat composition is applied and adhered, thereby acting as a substrate for the catalyst composition.

[0182] Ceramic substrates may be made of any suitable refractory material, e.g, cordierite, cordierite--alwnina, alwninum titanate, silicon titanate, silicon carbide, silicon nitride, zircon mullite, spodumene, alumina.-silica-magnesia, zircon silicate, sillimanite, a magnesium silicate, zircon, petalite, -alumina, an aluminosilicate and the like.

[0183] Substrates may also be metallic, comprising one or more metals or metal alloys. A metallic substrate may include any metallic substrate, such as those with openings or punch-outs in the channel walls. The metallic substrates may be employed in various shapes such as, e.g., pellets, corrugated sheet, or monolithic foam. Specific examples of metallic substrates include, but are not limited to, heat-resistant, base-metal alloys, especially those in which iron is a substantial or major component. Such alloys may contain one or more of nickel, chromium, and aluminum, and the total of these metals may advantageously comprise at least about 15 wt. % (weight percent) of the alloy, for instance, about 10% to about 25 wt. % chromium, about 1% to about 8 wt. % of aluminum, and from 0% to about 20 wt % of nickel, in each case based on the weight of the substrate. Examples of metallic substrates include, but are not limited to, those having straight channels; those having protruding blades along the axial channels to disrupt gas flow and to open communication of gas flow between channels; and those having blades and also holes to enhance gas transport between channels allowing for radial gas transport throughout the monolith. Metallic substrates, in particular, may be advantageously employed in certain embodiments in a close-coupled position, allowing for fast heat-up of the substrate and, correspondingly_fast heat up of a catalyst composition coated therein (e.g., an oxidation catalyst composition).

[0184] Any suitable substrate for the catalytic articles disclosed herein may be employed, such as a monolithic substrate of the type having fine, parallel gas flow passages extending there through from an inlet or an outlet face of the substrate such that passages are open to fluid flow there through (flow-through substrate). Another suitable substrate is of the type having a plurality of fine, substantially parallel gas flow passages extending along the longitudinal axis of the substrate where, typically, each passage is blocked at one end of the substrate body, with alternate passages blocked at opposite end-faces (wall-flow filter). Flow-through and wall-flow substrates are also taught, for example, in international Application Publication No. WO2016/070090, which is incorporated herein by reference in its entirety.

[0185] In some embodiments, the catalyst substrate comprises a honeycomb substrate in the form of a wall-flow filter or a flow-through substrate. In some embodiments, the substrate is a wall-flow filter. Flow-through substrates and wall-flow filters will be further discussed herein below.

Flow-Through Substrates

[0186] In some embodiments, the substrate is a flow-through substrate (e.g., monolithic substrate, including a flow-through honeycomb monolithic substrate). Flow-through substrates have fine, parallel gas flow passages extending from an inlet end to an outlet end of the substrate such that passages are open to fluid flow. The passages, which are essentially straight paths from their fluid inlet to their fluid outlet, are defined by walls on which a catalytic coating is disposed so that gases flowing through the passages contact the catalytic material. The flow passages of the flow-through substrate are thin-walled channels, which can be of any suitable cross-sectional shape and size such as trapezoidal, rectangular, square, sinusoidal, hexagonal, oval, circular, etc. The flow-through substrate can be ceramic or metallic as described above.

[0187] Flow-through substrates can, for example, have a volume of from about 50 in.sup.3 to about 1200 in.sup.3, a cell density (inlet openings) of from about 60 cells per square inch (cpsi) to about 500 cpsi or up to about 900 cpsi, for example, from about 200 to about 400 cpsi and a wall thickness of from about 50 to about 200 microns or about 400 microns. FIGS. 1A and 1B illustrate an exemplary substrate 2 in the form of a flow-through substrate coated with a catalyst composition as described herein. Referring to FIG. 1A, the exemplary substrate 2 has a cylindrical shape and a cylindrical outer surface 4, an upstream end face 6 and a corresponding downstream end face 8, which is identical to end face 6. Substrate 2 has a plurality of fine, parallel gas flow passages 10 formed therein. As seen in FIG. 1B, flow passages 10 are formed by walls 12 and extend through carrier 2 from upstream end face 6 to downstream end face 8, the passages 10 being unobstructed so as to permit the flow of a fluid, e.g., a gas stream, longitudinally through carrier 2 via gas flow passages 10 thereof. As more easily seen in FIG. 1B, walls 12 are so dimensioned and configured that gas flow passages 10 have a substantially regular polygonal shape. As shown, the catalyst composition can be applied in multiple, distinct layers if desired. In the illustrated embodiment, the catalyst composition consists of both a discrete bottom layer 14 adhered to the walls 12 of the carrier member and a second discrete top layer 16 coated over the bottom layer 14. The present disclosure can be practiced with one or more two, three, or tour or more) catalyst composition layers and is not limited to the two-layer embodiment illustrated in FIG. 1B. Further coating configurations are disclosed herein below.

Wall-Flow Filter Substrates

[0188] In some embodiments, the substrate is a wall-flow filter, which generally has a plurality of fine, substantially parallel gas flow passages extending along the longitudinal axis of the substrate. Typically, each passage is blocked at one end of the substrate body, with alternate passages blocked at opposite end-faces. Such monolithic wall-flow filter substrates may contain up to about 900 or more flow passages (or cells) per square inch of cross-section, although far fewer may be used. For example, the substrate may have from about 7 to 600, more usually from about 100 to 400, cells per square inch (cpsi). The cells can have cross-sections that are rectangular, square, circular, oval, triangular, hexagonal, or are of other polygonal shapes.

[0189] A cross-section view of a monolithic wall-flow filter substrate section is illustrated in FIG. 2, showing alternating plugged and open passages (cells). Blocked or plugged ends 100 alternate with open passages 101, with each opposing end open and blocked, respectively.

[0190] The filter has an inlet end 102 and outlet end 103. The arrows crossing porous cell walls 104 represent exhaust gas flow entering the open cell ends, diffusion through the porous cell walls 104 and exiting the open outlet cell ends. Plugged ends 100 prevent gas flow and encourage diffusion through the cell walls. Each cell wall will have an inlet side 104a and outlet side 104b. The passages are enclosed by the cell walls.

[0191] The wall-flow filter article substrate may have a volume of, for instance, from about cm.sup.3, about 100 cm.sup.3, about 200 cm.sup.3, about 300 cm.sup.3, about 400 cm.sup.3, about 500 cm.sup.3, about 600 cm.sup.3, about 700 cm.sup.3, about 800 cm.sup.3, about 900 cm.sup.3 or about 1000 cm.sup.3 to about 1500 cm.sup.3, about 2000 cm.sup.3, about 2500 cm.sup.3, about 3000 cm.sup.3, about 3500 cm.sup.3, about 4000 cm.sup.3, about 4500 cm.sup.3 or about 5000 cm.sup.3. Wall-flow filter substrates typically have a wall thickness from about 50 microns to about 2000 microns, for example, from about 50 microns to about 450 microns or from about 150 microns to about 400 microns.

[0192] The walls of the wall-flow filter are porous and generally have a wall porosity of at least about 50% or at least about 60% with an average pore size of at least about 5 microns prior to disposition of the functional coating. For instance, the wall-flow filter article substrate in some embodiments will have a porosity of 50%, 60%, 65% or 70%. For instance, the wall-flow filter article substrate will have a wall porosity of from about 50%, about 60%, about 65% or about 70% to about 75%, about 80% or about 85% and an average pore size of from about 5 microns, about 10 microns, about 20 microns, about 30 microns, about 40 microns or about 50 microns to about 60 microns, about 70 microns, about 80 microns, about 90 microns or about 100 microns prior to disposition of a catalytic coating.

[0193] As used herein, the terms wall porosity and substrate porosity mean the same thing and are used interchangeably. Porosity is the ratio of void volume divided by the total volume of a substrate. Pore size may be determined according to ISO15901-2 (static volumetric) procedure for nitrogen pore size analysis. Nitrogen pore size may be determined. on Micromeritics TRISTAR 3000 series instruments. Nitrogen pore size may be determined using BJH (Barrett-Joyner-Halenda) calculations and 33 desorption points. In some embodiments, useful wall-flow filters have high porosity, allowing high loadings of catalyst compositions without excessive backpressure during operation,

Coating Compositions and Configurations

[0194] To produce catalytic articles of the present disclosure, a substrate as described herein is contacted with an oxidation catalyst composition as disclosed herein to provide a coating (i.e., a slurry comprising particles of the catalyst composition are disposed on a substrate). The coatings of the oxidation catalyst composition on the substrate are referred to herein, e.g., as catalytic coating compositions or catalytic coatings. As used herein, the terms catalyst composition and catalytic coating composition are synonymous.

[0195] Oxidation catalyst compositions as disclosed herein may be prepared using a binder, for example, a ZrO.sub.2 binder derived from a suitable precursor such as zirconyl acetate or any other suitable zirconium precursor such as zirconyl nitrate. Zirconyl acetate binder provides a coating that remains homogeneous and intact after thermal aging, for example, when the catalyst is exposed to high temperatures of at least about 600 C., for example, about 800 C. and higher water vapor environments of about 5% or more. Other potentially suitable binders include, but are not limited to, alumina and silica. Alumina binders include aluminum oxides, aluminum hydroxides, and aluminum oxyhydroxides. Alwninwn salts and colloidal forms of alumina many also be used. Silica binders include various forms of SiO.sub.2, including silicates and colloidal silica. Binder compositions may include any combination of zirconia, alumina, and silica. Other exemplary hinders include, but are not limited to, boehemite, gamma-alumina, or delta/theta alumina, as well as silica sol. When present, the binder is typically used in an amount of about 1-5 wt % of the total washcoat loading. Alternatively, the binder can be zirconia-based or silica-based, for example zirconium acetate, zirconia sol, or silica sol. When present, the alumina binder is typically used in an amount of about 0.05 g/in.sup.3 to about 1 g/in.sup.3. In some embodiments, the binder is alumina.

[0196] The present catalytic coating may comprise one or more coating layers, where at least one layer comprises the present (oxidation) catalyst composition. The present catalytic coating may comprise a. single layer or multiple coating layers, The catalytic coating may comprise one or more thin, adherent coating layers disposed on and in adherence to least a portion of a substrate. The entire coating comprises the individual coating layers.

[0197] In some embodiments, the present catalytic articles may include the use of one or more catalyst layers and combinations of one or more catalyst layers. Catalytic materials may be present on the inlet side of the substrate wall alone, the outlet side alone, both the inlet and outlet sides, or the wall itself may consist all, or in part, of the catalytic material. The catalytic coating may be on the substrate wall surfaces and/or in the pores of the substrate walls, that is in and/or on the substrate walls. Thus, the phrase a catalytic coating disposed on the substrate means on any surface, for example, on a wall surface and/or on a pore surface,

[0198] The present catalyst compositions may typically be applied in the form of a washcoat, containing support material having catalytically active species thereon. A washcoat is formed by preparing a slurry containing a specified solids content (e.g., about 10% to about 60% by weight) of supports in a liquid vehicle, which is then applied to a substrate and dried and calcined to provide a coating layer. If multiple coating layers are applied, the substrate is dried and calcined after each layer is applied and/or after the number of desired multiple layers are applied. In one or more embodiments, the catalytic material(s) are applied to the substrate as a washcoat. Binders may also be employed as described above.

[0199] The above-noted catalyst composition(s) are generally independently mixed with water to form a slurry for purposes of coating a catalyst substrate, such as a honeycomb-type substrate. In addition to the catalyst particles, the slurry may optionally contain a binder (e.g., alumina, silica), water-soluble or water-dispersible stabilizers, promoters, associative thickeners, and/or surfactants (including anionic, cationic, non-ionic or amphoteric surfactants). A typical pH range for the slurry is about 3 to about 6. Addition of acidic or basic species to the slurry can be carried out to adjust the pH accordingly. For example, in some embodiments, the pH of the slurry is adjusted by the addition of amtnoniutn hydroxide or aqueous nitric acid.

[0200] The slurry can be milled to enhance mixing of the particles and formation of a homogenous material. The milling can be accomplished in a ball mill, continuous mill, or other similar equipment, and the solids content of the slurry may be, e.g., about 20-60 wt %, more particularly about 20-40 wt %. In some embodiments, the post-milling slurry is characterized by a D90 particle size of about 10 microns to about 40 microns, such as, e.g., 10 microns to about 30 microns, such as, e.g., about 10 microns to about 15 microns.

[0201] The slurry is then coated on the catalyst substrate using any washcoat technique known in the art. In some embodiments, the catalyst substrate is dipped one or more times in the slurry or otherwise coated with the slimy. Thereafter, the coated substrate is dried at an elevated temperature (e.g., 100-150 C.) for a period of time (e.g., 10 min-3 hours) and then calcined by heating, e.g., at 400-600 C., typically for about 10 minutes to about 3 hours. Following drying and calcining, the final washcoat coating layer can be viewed as essentially solvent-free.

[0202] After calcining, the catalyst loading obtained by the above described washcoat technique can be determined through calculation of the difference in coated and uncoated weights of the substrate. As will be apparent to those of skill in the art, the catalyst loading can be modified by altering the slurry rheology. In addition, the coating/drying/calcining process to generate a washcoat can be repeated as needed to build the coating to the desired loading level or thickness, meaning more than one washcoat may be applied.

[0203] In some embodiments, the catalytic article comprises a catalytic coating disposed on at least a portion of the substrate, the catalytic coating comprising a first washcoat and a second washcoat. In some embodiments, the first washcoat comprises a manganese component and a first refractory metal oxide support material, each as described herein. In some embodiments, the manganese component is supported on the first refractory metal oxide support material as manganese oxide or as a mixed oxide.

[0204] In some embodiments, the second washcoat comprises a platinum group metal (PGM) component comprising palladium and a second refractory metal oxide support material, each as described herein. In some embodiments, the PGM component is supported on the second refractory metal oxide support material.

[0205] The washcoats can be applied such that different coating layers may be in direct contact with the substrate. Alternatively, one or more undercoats may be present, so that at least a portion of a catalytic or sorbent coating layer or coating layers are not in direct contact with the substrate (but rather, are in contact with the undercoat). One or more overcoats may also be present, so that at least a portion of the coating layer or layers are not directly exposed to a gaseous stream or atmosphere (but rather, are in contact with the overcoat). The present catalyst composition may be in a bottom layer over a substrate.

[0206] Alternatively, the present catalyst composition may be in a top coating layer over a bottom coating layer. The catalyst composition may be present in a top and a bottom layer. Any one layer may extend the entire axial length of the substrate, for instance, a bottom layer may extend the entire axial length of the substrate and a top layer may also extend the entire axial length of the substrate over the bottom layer. Each of the top and bottom layers may extend from either the inlet or outlet end.

[0207] For example, both bottom and top coating layers may extend from the same substrate end where the top layer partially or completely overlays the bottom layer and where the bottom layer extends a partial or full length of the substrate and where the top layer extends a partial or full length of the substrate. Alternatively, a top layer may overlay a portion of a bottom layer. For example, a bottom layer may extend the entire length of the substrate and the top layer may extend about 10%, about 20%, about 30%, about 40%, about 50%, about 60%, about 70%, about 80%, or about 90% of the substrate length, from either the inlet or outlet end.

[0208] Alternatively, a bottom layer may extend about 10%, about 15%, about 25%, about 30%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, or about 95% of the substrate length from either the inlet end or outlet end and a top layer may extend about 10%, about 15%, about 25%, about 30%, about 40%, about 45%, about 50%, about 55%. about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, or about 95% of the substrate length from either the inlet end of outlet end, wherein at least a portion of the top layer overlays the bottom layer. This overlay zone may, for example, extend from about 5% to about 80% of the substrate length, for example, about 5%, about 10%, about 20%, about 30%, about 40%, about 50%, about 60%, or about 70% of the substrate length.

[0209] Top and/or bottom coating layers may be in direct contact with the substrate, Alternatively, one or more undercoats may be present, so that at least a portion of the top and/or the bottom coating layers are not in direct contact with the substrate (but rather with the undercoat). One or more overcoats may also be present, so that at least a portion of the top and/or bottom coating layers are not directly exposed to a gaseous stream or atmosphere (but rather are in contact with the overcoat). An undercoat is a layer under a coating layer, an overcoat is a layer over a coating layer, and an interlayer is a layer between two coating layers.

[0210] The top and bottom coating layers may be in direct contact with each other without any interlayer. Alternatively, different coating layers may not be in direct contact, with a gap between the two zones. An interlayer, if present, may prevent the top and bottom layers from being in direct contact. An interlayer may partially prevent the top and bottom layers from being in direct contact and thereby allow for partial direct contact between the top and bottom layers. The interlayer(s), undercoat(s), and overcoat(s) may contain one or more catalysts or may be free of catalysts. The present catalytic coatings may comprise more than one identical layers, for instance, more than one lavez containing compositions.

[0211] The catalytic coating may advantageously be zoned, comprising zoned catalytic layers, that is, where the catalytic coating contains varying compositions across the axial length of the substrate. This may also be described as laterally zoned. For example, a laser may extend from the inlet end towards the outlet end, extending about 10%, about 20%, about 30%, about 40%, about 50%, about 60%. about 70%, about 80%, or about 90% of the substrate length. Another layer may extend from the outlet end towards the inlet end, extending about 10%, about 20%, about 30%, about 40%, about 50%, about 60%, about 70%, about 80%, or about 90% of the substrate length. Different coating layers may be adjacent to each other and not overlay each other. Alternatively, different layers may overlay a portion of each other, providing a third middle zone. The middle zone may, for example, extend from about 5% to about 80% of the substrate length, for example, about 5%, about 10%, about 20%, about 30%. about 40%, about 50%, about 60%, or about 70% of the substrate length.

[0212] Different layers may each extend the entire length of the substrate or may each extend a portion of the length of the substrate and may overlay or underlay each other, either partially or entirely. Each of the different layers may extend from either the inlet or outlet end. Different catalytic compositions may reside in each separate coating layer. The present catalytic coatings may comprise more than one identical layer.

[0213] Zones of the present disclosure are defined by the relationship of coating layers. With respect to different coating layers, there are a number of possible zoning configurations. For example, there may be an upstream zone and a downstream zone, there may be an upstream zone, a middle zone and a downstream zone, there may four different zones, etc. Where two layers are adjacent and do not overlap, there are upstream and downstream zones. Where two layers overlap to a certain degree, there are upstream, downstream and middle zones. Where for example, a coating layer extends the entire length of the substrate and a different coating layer extends from the outlet end a certain length and overlays a portion of the first coating layer, there are upstream and downstream zones.

[0214] In some mbodiments, first and second coating layers may be overlaid, either first over second or second over first (i.e., top/bottom), for example, where the first coating layer extends from the inlet end towards the outlet end and where the second coating layer extends from the outlet end towards the inlet end. In this case, the catalytic coating will comprise an upstream zone, a middle (overlay) zone and a downstream zone. The first and/or second coaling layers may be synonymous with the above top and/or bottom layers described above.

[0215] In some embodiments, a first coating layer may extend from the inlet end towards the outlet end and a second coating layer may extend from the outlet end towards the inlet end, where the layers do not overlay each other, for example they may be adjacent.

[0216] FIGS. 3A, 3B, and 3C show some possible coating layer configurations with two coating layers, wherein at least one of said coating layers comprises the catalyst composition as disclosed herein. Shown are substrate walls 200 onto which coaling layers 201 (top coat) and 202 (bottom coat) are disposed. These are simplified illustrations, and in the case of a. porous wall-flow substrate, not shown are pores and coatings in adherence to pore walls and not shown are plugged ends. In FIG. 3A, coating layers 201 and 202 each extend the entire length of the substrate with top layer 201 overlaying bottom layer 202. The substrate of FIG. 3A does not contain a zoned coating configuration. In FIG. 3B, bottom coating layer 202 extends from the outlet about 50% of the substrate length and top coating layer 201 extends from the inlet greater than 50% of the length and overlays a portion of layer 202, providing an upstream zone 203, a middle overlay zone 205 and a downstream zone 204. In FIG. 3C, coating layer 202 extends from the outlet about 50% of the substrate length and coating layer 201 extends from the inlet greater than 50% of the length and overlays a portion of layer 202, providing an upstream zone 203, a middle overlay zone 205, and a downstream zone 204. FIGS. 3A, 3B, and 3C may be useful to illustrate coating compositions on a wall-through substrate or the flow-through substrate.

[0217] In some embodirnerits, the first and second washcoats are substantially free of copper. In some embodiments, the first washcoat is disposed directly on the substrate, and the second washcoat is on at least a portion of the first washcoat. In some embodiments, the second washcoat is disposed directly on the substrate, and the first washcoat is on at least a portion of the second washcoat.

[0218] In some embodiments, the catalytic article has a zoned configuration, wherein the first washcoat is disposed directly on the substrate from the outlet end to a length from about 20% to about 100% of the overall length; and the second washcoat is disposed on the substrate from the inlet end to a length from about 20% to about 100% of the overall length. In some embodiments, the catalytic article has a zoned configuration, wherein the second washcoat is disposed directly on the substrate from the outlet end to a length from about 20% to about 100% of the overall length; and the first washcoat is disposed on the substrate from the inlet end to a length from about 20% to about 100% of the overall length.

[0219] The present (oxidation) catalytic coating, as well as any zone or any layer or any section of a coating, is present on the substrate at a loading (concentration) of, for instance, from about 0.3 g/in.sup.3 to about 6.0 g/in.sup.3, or from about 0.4, about 0.5, about 0.6, about 0.7, about 0.8, about 0.9 or about 1.0 g/in.sup.3 to about 1.5 g/in.sup.3, about 2.0 g/in.sup.3, about 2.5 g/in.sup.3, about 3.0 g/in.sup.3, about 3.5 g/in.sup.3, about 4.0 g/in.sup.3, about 4.5 g/in.sup.3, about 5.0 g/in.sup.3 or about 5.5 g/in.sup.3, based on the volume of the substrate. This refers to dry solids weight per volume of substrate, for example per volume of a honeycomb monolith. Concentration is based on a cross-section of a substrate or on an entire substrate. In some embodiments, a top coating layer is present at a lower loading than the bottom coating layer.

[0220] The loading of the PGM component (e.g., palladium, and optionally platinum) of the disclosed oxidation catalyst composition on the substrate may be in the range of about 2 g/ft.sup.3, about 5 g/ft.sup.3, or about 10 g/ft.sup.3 to about 250 g/ft.sup.3, for example from about 20 g/ft.sup.3, about 30 g/ft.sup.3, about 40 g/ft.sup.3, about 50 g/ft.sup.3 or about 60 g/ft.sup.3 to about 100 g/ft.sup.3, about 150 g/ft.sup.3or about 200 g/ft.sup.3, about 210 g/ft.sup.3, about 220 g/ft.sup.3, about 230 g/ft.sup.3, about 240 g/ft.sup.3 or about 250 g/ft.sup.3, based on the volume of the substrate. The PGM is, for example, present in a catalytic layer from about 0.1 wt %, about 0.5 wt %, about 1.0 wt %, about 1.5 wt % or about 2.0 wt % to about 3 wt %, about 5 wt %, about 7 wt %, about 9 wt %, about 10 wt %, about 12 wt % or about 15 wt %, based on the weight of the layer.

Catalyst Activity

[0221] In some embodiments, the level of hydrocarbons, e.g., methane, or CO present in the exhaust gas stream is reduced compared to the level of hydrocarbons or CO present in the exhaust gas stream prior to contact w catalyst article. In some embodiments, the efficiency for reduction of HC and/or CO level is measured in terms of the conversion efficiency. In some embodiments, conversion efficiency is measured as a function of light-off temperature (i.e., T.sub.50 or T.sub.70). The T.sub.50 or T.sub.70 light-off temperature is the temperature at which the catalyst composition is able to convert 50% or 70%, respectively, of hydrocarbons or carbon monoxide to carbon dioxide and water. Typically, the lower the measured light-off temperature for any given catalyst composition, the more efficient the catalyst composition is to carry out the catalytic reaction, e.g., hydrocarbon conversion.

[0222] In some embodiments, the level of nitrogen dioxide (NO.sub.2) in the exhaust gas stream is increased compared to the level of NO.sub.2 present in the exhaust gas stream prior to contact with the catalyst article. Such an increase in NO.sub.2 content is generally beneficial in promoting the catalytic activity of a downstream SCR catalyst.

Exhaust Gas Treatment Systems

[0223] In another aspect is provided a system for treatment of an exhaust gas stream from an internal combustion engine containing hydrocarbons (HCs), carbon monoxide (CO), and nitrogen oxides (NO.sub.x). The system comprises a diesel oxidation catalyst (DOC) article as to described herein located downstream of the internal combustion engine. The engine can be, e.g., a diesel engine which operates at combustion conditions with air in excess of that required for stoichiometric combustion, i.e., lean conditions. In other embodiments, the engine can be a gasoline engine a lean burn gasoline engine) or an engine associated with a stationary source (e.g, electricity generators or pumping stations) Exhaust gas treatment systems generally contain more than one catalytic article positioned downstream from the engine in fluid communication with the exhaust gas stream, A system may contain, for instance, oxidation catalyst article as disclosed herein (e.g., a DOC), a selective catalytic reduction catalyst (SCR), and one or more articles including a reductant injector, a soot filter, an ammonia oxidation catalyst (AMOx), or a lean NO.sub.x trap (LNT). An article containing a reductant injector is a reduction article. A reduction system includes a reductant injector and/or a pump and/or a reservoir, etc. The present treatment system may further comprise a soot filter and/or an ammonia oxidation catalyst. A soot filter may be uncatalyzed or may be catalyzed (CSF), such as a CSF as disclosed herein. For instance, the present treatment system may comprise, from upstream to downstreaman article containing a DOC, a CSF, a urea injector, a SCR article and an article containing an AMOx. A lean NO.sub.x trap (LNT) may also be included.

[0224] The relative placement of the various catalytic components present within the emission treatment system can vary. In the present exhaust gas treatment systems and methods, the exhaust gas stream is received into the article(s) or treatment system by entering the upstream end and exiting the downstream end. The inlet end of a substrate or article is synonymous with the upstream end or front end. The outlet end is synonymous with the downstream end or rear end. The treatment system is, in general, downstream of and in fluid communication with an internal combustion engine.

[0225] One exemplary emission treatment system is illustrated in FIG. 4, which depicts a schematic representation of an emission treatment system 20. As shown, the emission treatment system can include a plurality of catalyst components in series downstream of an engine 22, such as a lean burn engine. At least one of the catalyst components will comprise the oxidation catalyst composition of the disclosure as set firth herein (e.g., a DOC, a CSF, or both). The oxidation catalyst composition of the disclosure could be combined with numerous additional catalyst materials and could be placed at various positions in comparison to the additional catalyst materials. FIG. 4 illustrates five catalyst components, 24, 26, 28, 30, 32 in series; however, the total number of catalyst components can vary and five components to is merely one example.

[0226] Without limitation, Table 1 presents various exhaust gas treatment system configurations of one or more embodiments of this disclosure. It is noted that each catalyst is connected to the next catalyst via exhaust conduits such that the engine is upstream of catalyst A, which is upstream of catalyst B, which is upstream of catalyst C, which is upstream of catalyst D, which is upstream of catalyst E (when present). The reference to Components A-E in the table can be cross-referenced with the same designations in FIG. 5.

[0227] The DOC catalyst noted in Table 1 can be any catalyst conventionally used as a diesel oxidation catalyst to effectively convert CO and HC to CO.sub.2 and H.sub.2O.

[0228] The ccDOC catalyst noted in Table 1 can be any catalyst conventionally used as a diesel oxidation catalyst, located in a close-coupled position toward the engine block, to convert CO and HC to CO.sub.2 and H.sub.2O, and which generates heat through the reaction exotherm to effectively heat downstream catalysts.

[0229] The DOC(BMO) catalyst noted in Table 1 can be any catalyst conventionally used as a diesel oxidation catalyst to convert CO and HC to CO.sub.2 and H.sub.2O, and which does not include a platinum group metal (PGM). The BMO is denoted as base metal oxides as defined herein. The combination of Component A (DOC)+Component B (DOC(BMO)) is expressed as an arrangement of Component A located upstream of Component B, either in the same canister or in two separate canisters.

[0230] The DOC+BMO catalyst noted in Table 1 is a diesel oxidation catalyst comprising both PGM and BMO components on the same substrate.

[0231] The LNT catalyst noted in Table 1 can be any catalyst conventionally used as a NO.sub.x trap, and typically comprises NO.sub.x-adsorber compositions that include base metal oxides (BaO, MgO, CeO.sub.2, and the like) and a platinum group metal for catalytic NO oxidation and reduction (e.g:, Pt and Rh).

[0232] The LT-NA catalyst noted in Table 1 can be any catalyst that can adsorb NO.sub.x (e.g. . NO or NO.sub.2) at low temperatures (<250 C.) and release it to the gas stream at high temperatures (>250 C.). The released NO.sub.x is generally converted to N.sub.2 and H.sub.2 O over a down-stream SCR or SCRoF catalyst. Typically, a LT-NA catalyst comprises Pd-promoted zeolites or Pd-promoted refractory metal oxides.

[0233] Reference to SCR in the table refers to an SCR catalyst. Reference to SCRoF (or SCR on filter) refers to a particulate or soot filter (e.g., a wall-flow filter), which can include an SCR catalyst composition.

[0234] Reference to AMOx in the table refers to an ammonia oxidation catalyst, which can be provided downstream of the catalyst of one more embodiments of the disclosure to remove any slipped ammonia from the exhaust gas treatment system. In some embodiments, the AMOx catalyst may comprise a PGM component. In some embodiments, the AMOx catalyst may comprise a bottom coat with PGM and a top coat with SCR functionality.

[0235] As will be recognized by one skilled in the art, in the configurations listed in Table 1, any one or more of components A, B, C, D, or E can be disposed on a particulate filter, such as a wall flow filter, or on a flow-through honeycomb substrate. In some embodiments, an engine exhaust system comprises one or more catalyst compositions mounted in a position near the engine (in a close-coupled position, CC), with additional catalyst compositions in a position underneath the vehicle body (in an underfloor position, UF). In some embodiments, the exhaust gas treatment system may further comprise a urea injection component.

TABLE-US-00001 TABLE 1 Possible exhaust gas treatment system configurations Component Component Component Component Component A B C D E ccDOC DOC SCR Optional (or SCRoF) AMOx DOC DOC SCR Optional (BMO) (or SCRoF) AMOx DOC + SCR Optional BMO (or SCRoF) AMOx DOC LT-NA CSF SCR Optional AMOx - LT-NA DOC CSF SCR Optional AMOx DOC LT-NA SCR CSF Optional AMOx LT-NA DOC SCR CSF Optional AMOx DOC LT-NA/DOC SCR Optional AMOx DOC LT-NA/DOC LNT SCR Optional AMOx

Method of Treating an Exhaust Gas Stream

[0236] Aspects of the current disclosure are directed towards a method for treating an engine exhaust gas stream comprising hydrocarbons and/or carbon monoxide, and/or NO.sub.x, the method comprising contacting the exhaust gas stream with the catalytic article of the present disclosure, or the emission treatment system of the present disclosure.

[0237] In general, hydrocarbons (HCs) and carbon monoxide (CO) present in the exhaust gas stream of any engine can be converted to carbon dioxide and water. Typically, hydrocarbons present in engine exhaust gas stream comprise C.sub.1-C.sub.6 hydrocarbons (i.e., lower hydrocarbons), such as methane, although higher hydrocarbons (greater than C.sub.6) can also be detected. In some embodiments, the method comprises contacting the gas stream with the catalytic article or the exhaust gas treatment system of the present disclosure, for a time and at a temperature sufficient to reduce the levels of CO and or HC in the gas stream.

[0238] In general, NO.sub.x species such as NO present in the exhaust gas stream of any engine can be converted (oxidized) to NO.sub.2. In some embodiments, the method comprises contacting the gas stream with the catalytic article or the exhaust gas treatment system of the present disclosure, for a time and at a temperature sufficient to oxidize at least a portion of the NO present in the gas stream to NO.sub.2.

[0239] The present articles, systems, and methods are suitable for treatment of exhaust gas streams from mobile emissions sources such as trucks and automobiles. The present articles, systems and methods are also suitable for treatment of exhaust streams from stationary sources such as power plants.

[0240] it will be readily apparent to one of ordinary skill in the relevant arts that suitable modifications and adaptations to the compositions, methods, and applications described herein can be made without departing from the scope of any embodiments or aspects thereof. The compositions and methods provided are exemplary and are not intended to limit the scope of the claimed embodiments. All of the various embodiments, aspects, and options disclosed herein can be combined in all variations. The scope of the compositions, formulations, methods, and processes described herein include all actual or potential combinations of embodiments, aspects, options, examples, and preferences herein. All patents and publications cited herein are incorporated by reference herein for the specific teachings thereof as noted, unless other specific statements of incorporation are specifically provided.

EXAMPLES

[0241] This disclosure is more fully illustrated by the following examples, which are set forth to illustrate the present subject matter and is not to be construed as limiting thereof Unless otherwise noted, all parts and percentages are by weight, and all weight percentages are expressed on a dry basis, meaning excluding water content, unless otherwise indicated.

Example 1A

Pd on Lanthanum-Containing Zirconia Support

[0242] A sample of 2% palladium on a lanthanum-containing zirconia was prepared. A measured amount of Pd nitrate solution was impregnated onto a La-containing zirconia support (containing about 9% lanthanum oxide by weight), resulting in a coated powder with 2% by weight of Pd, based on the total weight of the impregnated support. The Pd impregnated support powder was added to deionized water (solid content of the slurry was 30 wt %). The slurry was milled to a particle size with D90 less than 15 m using a ball mill. The milled slurry was dried at 12.0 C. under stirring and calcined at 590 C. for 2 hours in air. The calcined sample was cooled in air until reaching room temperature. The calcined powder was crushed and sieved to a particle size in the range of 250-500 m. The sieved powder was divided into two portions. The first portion was evaluated as the fresh sample. The second portion was aged in air with 10% steam for 16 hours at 800 C., to provide an aged sample.

Example 1B

Pt and Pd on Alumina Support

[0243] A sample of platinum and palladium (2% total PGM by weight) on an alumina support was prepared. Platinum nitrate and palladium nitrate (Pt and Pd in a ratio by weight of 2:1) were by impregnated on high surface area alwnina (surface area of about 150 m.sup.2/g) according to standard procedures. The 2% PGM impregnated alumina support powder was added to deionized water (solid content of the slurry was 30 wt. %). The slurry was milled to a particle size with D 90 less than 15 m using a ball mill. The milled slurry was dried at 120 C., under stirring and calcined at 590 C. for 2 hours in air. The calcined sample was cooled in air until reaching room temperature. The calcined powder was crushed and sieved to a particle size in the range of 250-500 m. The sieved powder was divided into two portions. The first portion was evaluated as the fresh sample. The second portion was aged in air with 10% steam for 16 hours at 800 C., to provide an aged sample.

Example 2

Ce/Mn Doped Alumina Support

[0244] A base metal oxide material was prepared by impregnation of ceriwn nitrate onto an alumina support, followed by drying. The cerium-impregnated alumina support was then impregnated with manganese nitrate, dried, calcined, crushed, and sieved as in Examples 1A and 1B to provide a Ce/Mn doped alumina support material (particle size in the range of 250-500 m) containing 10% ceria and 10% manganese oxide by weight on alumina, based on the total weight of the doped alumina support material. The sieved powder was divided into two portions. The first portion was evaluated as the fresh sample. The second portion was aged in air with 10% steam for 16 hours at 800 C., to provide an aged sample,

Example 3

Mn Doped Lanthanum-Containing Zirconia Support

[0245] A base metal oxide material was prepared by impregnation of manganese nitrate onto a La-containing zirconia support (containing about 9% lanthanum oxide by weight) using the procedure of Example 2, but replacing alumina with La-zirconia and eliminating the cerium nitrate. After calcination, the resulting powder had about 10% Mn content by weight, calculated as the oxides and based on the total weight of the impregnated support.

Example 4

Ce/Mn Doped Lanthanum-Containing Zirconia Support

[0246] A base metal oxide material was prepared by sequential impregnation of cerium nitrate and manganese nitrate onto a La-containing zirconia support (containing about 9% lanthanum oxide by weight) using the procedure of Example 3. After calcination, the resulting powder had about 10% Ce and 10% Mn content by weight, calculated as the oxides and based on the total weight of the impregnated support.

Example 5

Cu/Mn Doped Lanthanum-Containing Zirconia Support

[0247] A base metal oxide material was prepared by sequential impregnation of copper nitrate and manganese nitrate onto a La-containing zirconia support (containing about 9% lanthanum oxide by weight) using the procedure of Example 4, but substituting copper nitrate for the cerium nitrate. After calcination, the resulting powder had about 10% Cu and 10% Mn content by weight, calculated as the oxides and based on the total weight of the impregnated support.

Example 6

Ce/Cu/Mn Doped Lanthanum-Containing Zirconia Support

[0248] A base metal oxide material was prepared by sequential impregnation of cerium nitrate, copper nitrate and manganese nitrate onto a La-containing zirconia support (containing about 9% lanthanum oxide by weight) using the procedure of Example 5, but impregnating first with cerium nitrate. After calcination, the resulting powder had about 10% Ce, 10% Cu and 10% Mn content by weight, calculated as the oxides and based on the total weight of the impregnated support.

Examples 7-12

Pd Catalyst Articles

[0249] Catalyst articles were prepared from the powders of Examples 1A and 2-6. To prepare the articles, the appropriate powder samples (fresh and aged) were loaded into individual testing beds. The testing beds had a total volume of 1 milliliter, and two equal sections: a bottom and top, as shown in FIG. 5. In each case, the top portion was filled with the 2% Pd on La/Zr support powder of Example 1A, and the bottom portion of the testing bed was filled with a reference lanthanum-containing zirconia support (Example 7), or with the support of one of Examples 2-6 (Examples 8-12), mixed with an equal quantity of corundum. The composition of the articles is summarized in Table 2.

Example 13

Reference Pt/Pd Catalyst Article

[0250] A catalyst article was prepared from the powder of Example 1B. To prepare the article, the appropriate powder samples (fresh) were loaded into a testing bed. The testing bed had a total volume of 1 milliliter, and two equal sections: a bottom and top, as shown in FIG. 5. The top layer was filled with the 2% Pt/Pd (2:1 Pt/Pd) on alumina of Example 1B, and the bottom portion of the testing bed was filled with a reference lanthanum-containing zirconia support without additional dopants. The composition of the articles is summarized in Table 2:

Example 14

Pt/Pd Catalyst Article

[0251] A catalyst article was prepared from the powder of Example 1B. To prepare the article, the appropriate powder samples (fresh) were loaded into a testing bed. The testing bed had a total volume of 1 milliliter, and two equal sections: a bottom and top, as shown in FIG. 5. The top layer was filled with the 2% Pt/Pd (2:1 Pt/Pd) on alumina of Example 1B, and the bottom portion of the testing bed was filled with the Ce/Mn/La/ZrO.sub.2 support of Example 4. The composition of the articles is summarized in Table 2.

TABLE-US-00002 TABLE 2 Layer compositions of articles of Examples 7-14 Example # Top layer Bottom Layer 7 (Ref- 2% Pd on La/ZrO.sub.2 La/ZrO.sub.2, blended with erence) (Example 1A) corundum 8 2% Pd on La/ZrO.sub.2 Ce/Mn/Al.sub.2O.sub.3 (Example 2) (Example 1A) blended with corundum 9 2% Pd on La/ZrO.sub.2 Mn/La/ZrO.sub.2 (Example 3) (Example 1A) blended with corundum 10 2% Pd on La/ZrO.sub.2 Ce/Mn/La/ZrO.sub.2 (Example 4) (Example 1A) blended with corundum 11 2% Pd on La/ZrO.sub.2 Cu/Mn/La/ZrO.sub.2 (Example 5) (Example 1A) blended with corundum 12 2% Pd on La/ZrO.sub.2 Ce/Cu/Mn/La/ZrO.sub.2 (Example 6) (Example 1A) blended with corundum 13 (Ref- 2% 2:1 Pt/Pd on La/ZrO.sub.2 La/ZrO.sub.2, blended with erence) (Example 1B) corundum 14 2% 2:1 Pt/Pd on La/ZrO.sub.2 Ce/Mn/La/ZrO.sub.2 (Example 4) (Example 1B) blended with corundum

Example 15

Reactor Testing Light-Off Experiments

[0252] The articles of Examples 7-12 (both fresh and aged) and 13 and 14 (fresh; were evaluated for hydrocarbon (HC) and carbon monoxide (CO) light-off in a reactor under steady-state conditions. The gas feed was CO at 1250 ppm, ethylene at 100 ppm (CI basis), 2:1 decane-toluene mix at 300 ppm (C1 basis), nitric oxide at 180 ppm, carbon dioxide at 10%, water vapor at 10%, and oxygen (O.sub.2) at 10%. For steady-state light-off, a stepwise 3-minute equilibration time was used, plus a 30 second sampling time for temperatures from The first light-off test was treated as a de-greening of the sample, and the second light-off test was then recorded,

[0253] As a measure of the performance of fresh and aged catalysts the CO (T.sub.50_CO) and HC (T.sub.70_HC) light-off temperatures and NO.sub.2 yields were determined. The CO (T.sub.50_CO) and HC (T.sub.70_HC) light-off temperatures are provided in Table 3, which demonstrated that all inventive articles show improved HC conversion, for fresh or aged samples.

[0254] While the CeMn impregnated on alumina support (Example 8) provided improved HC performance over Example 7 (Reference article), the use of a lanthanum-containing zirconia support (Examples 9-12) instead of an alumina support further enhanced HC performance, fresh or aged. Without wishing to be bound by theory, this is indicative of a MnZr synergism whiCh was beneficial for enhancing HC performance. Surprisingly, the presence of both cerium and copper (Example 12) increased the RC light off temperature relative to samples with Cu and Mn, Mn alone, or Ce and Mn (Examples 11, 9, and 10, respectively).

[0255] While the reference catalyst article containing Pt/Pd impregnated alumina support (Example 13) provided improved RC/CO performance over Example 7 (Reference article), the addition of ceria and manganese on a lanthanum-containing zirconia support (Examples 14) further surprisingly enhanced HC performance (Table 3).

TABLE-US-00003 TABLE 3 HC/CO Light-Off (L/O) Temperatures State Example # HC.sub.70 L/O, C. CO.sub.50 L/O, C. Fresh Example 7 (Ref) 306 211 Example 8 272 209 Example 9 255 207 Example 10 252 209 Example 11 255 195 Example 12 271 193 Example 13 213 168 Example 14 203 167 Aged Example 7 (Ref) 332 225 Example 8 292 224 Example 9 284 225 Example 10 285 231 Example 11 286 217 Example 12 289 217

[0256] As a further performance measurement criterion, the NO.sub.2 yields were evaluated at an inlet temperature of 300 C. The data are provided in Table 4, which demonstrated that all inventive articles, either fresh or aged, offered significantly higher NO.sub.2 yield than the reference article (Example 7). The noted Mn-Zr synergism for HC light off was also beneficial for improving NO.sub.2 yield. This enhanced NO.sub.2 yield is expected to yield benefits to a downstream SCR catalyst, as shown in Table 4. In addition, this synergism enhanced NO.sub.2 performance stability against aging, while CeMn on alumina did not. Further, the addition of Cu onto the Mn/LaZr support (Examples 11 and 12) resulted in an enhanced CO conversion, fresh or aged. Surprisingly, however, the addition of Cu compromised FIC conversion and NO.sub.2 yield compared with Examples 9 and 10.

TABLE-US-00004 TABLE 4 NO.sub.2 yield at 300 C. State Example # NO.sub.2 yield, % Fresh Example 7 (Ref) 4 Example 8 29 Example 9 72 Example 10 87 Example 11 49 Example 12 36 Aged Example 7 (Ref) 4 Example 8 4 Example 9 53 Example 10 50 Example 11 35 Example 12 25

[0257] As a further perforniance measurement criterion for Examples 13 and 14, the NO.sub.2 yields were evaluated at an inlet temperature of 225 C. The data are provided in Table 5, which demonstrated that the inventive article of Example 14, even with Pt/Pd on alumina support as the top layer, offered significantly higher NO.sub.2 yield than the reference article (Example 13).

TABLE-US-00005 TABLE 5 NO.sub.2 yield at 225 C. State Example # NO.sub.2 yield, %@225 C. Fresh Example 13 (Ref) 28 Example 14 51

Example 16

Reactor Testing Light-Off Experiments with Formaldehyde

[0258] Formaldehyde emissions from automotive exhaust gas are now regulated in the United States. Accordimzly, the performance of the articles of Examples 7-12 was evaluated according to the protocol of Example 15, but adding formaldehyde (150 ppm) to the feed gas. The samples from Example 15 were cooled down from the second L/O run under a N.sub.2 atmosphere only prior to the light-off experiments. The data are provided in Table 6.

TABLE-US-00006 TABLE 6 HC/CO Light-Off (L/O) Temperatures and NO.sub.2 yield at 300 C. HC.sub.70 CO.sub.50 NO.sub.2 yield at State Example # L/O, C. L/O, C. 300 C., % Fresh Example 7 (Ref) 247 180 4 Example 8 245 184 40 Example 9 231 181 81 Example 10 231 182 90 Example 11 214 160 59 Example 12 241 180 46 Aged Example 7 (Ref) 288 192 3 Example 8 261 192 7 Example 9 251 188 59 Example 10 250 193 54 Example 11 260 191 37 Example 12 255 192 26

[0259] As demonstrated by the data in Table 6, a similar trend to that for Example 15 was observed; i.e., all inventive articles show improved. HC conversion, fresh or aged, and offered significantly higher NO.sub.2 yield than the Reference article (Example 7). The addition of Mn onto the La-containing zirconia support was beneficial for both HC conversion and NO.sub.2 yield.

Examples 16-17

Formaldehyde Oxidation Function Assessment

[0260] The above examples using powder catalysts were also tested in a configuration that feed gas passes through the catalysts from the top layer to the bottom layer, resembling a front zone and rear zone configuration in an exhaust gas treatment system using a honeycomb structure with washcoat coated onto the perimeter of the flow through channels. As the rear zone catalysts have no PGM, as shown in Examples 7-14, another set of experiments was carried out via blending PGM with the supports, as shown in Tables 7, 8, and 9. The procedures for making such a support as follows: a commercial zirconium oxide obtained has a surface area about 100 M.sup.2/g was impregnated with Pd nitrate solution so that the resulting washcoat has a Pd concentration on the support about 0.67%. After drying in an oven at 120 C. for an hour, this Pd impregnated powder was further impregnated with Pt-amine solution, resulting in a 1% Pt/Pd washcoat powder with Pt/Pd ratio to be 2/1. For La/ZrO.sub.2 (Example 16), a preformed La/ZrO.sub.2 was obtained commercially, with about 9% La on ZrO2.

[0261] The addition of Pt/Pd follows the same process as Example 15. For Zr/Al.sub.2O.sub.3 (Example 17), similar procedures were used as Example 15, except that the support is an aluminum oxide (alumina) with a surface area about 150 M.sup.2/g. Zr was impregnated onto the alumina as zirconium acetate solution, resulting in a support with 30% Zr, In this set of experiments, 1% Pt/Pd(2/1) was used throughout, since the Pt/Pd-containing catalysts offer a higher NO.sub.2 yield than those of the Pd-only catalysts (Table 5). As ZrO.sub.2 is the main element for the support used in the previous set of experiments (Examples 7-14, powder form), this new set of experiments was carried out in a 1Dx3L honeycomb structure (400 cpsicells per squire inches), using the zirconium oxide as the reference support. Formaldehyde conversion was the focus of this evaluation.

TABLE-US-00007 TABLE 7 Catalyst articles: Pt/Pd on various supports Example # Single washcoat layer 15A (Reference A) 1% 2:1 Pt/Pd on ZrO.sub.2 16 (Reference B) 1% 2:1 Pt/Pd on La/ZrO.sub.2 17 1% 2:1 Pt/Pd on Zr/Al.sub.2O.sub.3

Examples 18-22

Evaluation of Mn Amount

[0262] As Mn is the main element for the improvement observed in HC conversion (Example 9 versus Example 7 reference), the effects of differential amounts of Mn added to the supports were investigated, as shown in Tables 8 & 9. The Mn addition was carried out similar to Zr addition to the alumina support (Example 17), except Mn-acetate solution was used instead of Zr-acetate (Examples 18-22). Five different supports were investigated, as shown in Table 8, with 5% Mn on the supports.

TABLE-US-00008 TABLE 8 Catalyst articles: 1% Pt/Pd, with 5% Mn on various supports Example # Single washcoat layer Support compositions 18 (Ref- 1% 2:1 Pt/Pd with 5% ZrO.sub.2: about 100% erence C) Mn on ZrO.sub.2 19 (Ref- 1% 2:1 Pt/Pd with 5% La/ZrO.sub.2: about 9% La, 91% Zr erence D) Mn on La/ZrO.sub.2 20 1% 2:1 Pt/Pd with 5% Zr/Al.sub.2O.sub.3: about 30% Mn on Zr/Al.sub.2O.sub.3 Zr, 70% Al 21 1% 2:1 Pt/Pd with 5% La/Zr/Al.sub.2O.sub.3: about 3% Mn on La/Zr/Al.sub.2O.sub.3 La, 20% Zr, 77% Al 22 1% 2:1 Pt/Pd with 5% Zr/CeO.sub.2: about 30% Zr, 70% Ce Mn on Zr/CeO.sub.2

[0263] To investigate whether the increased amount of Mn on the support could impact HC/CO and HCHO conversions. 25% Mn on the various supports was tested under the same L/O protocol as the 5% Mn samples, as shown in Table 9.

TABLE-US-00009 TABLE 9 Catalyst articles: 1% Pt/Pd, with 25% Mn on various supports) Example # Single washcoat layer 18 (Reference E) 1% 2:1 Pt/Pd with 25% Mn on ZrO.sub.2 19 (Reference F) 1% 2:1 Pt/Pd with 25% Mn on La/ZrO.sub.2 20 1% 2:1 Pt/Pd with 25% Mn on Zr/Al.sub.2O.sub.3 21 1% 2:1 Pt/Pd with 25% Mn on La/Zr/Al.sub.2O.sub.3 22 1% 2:1 Pt/Pd with 25% Mn on Zr/CeO.sub.2

[0264] The steady-state light-off (L/0) experiments in a core reactor testing unit were carried out under the following protocol: CO: 1000 ppm, FICHO: 25 ppm, C.sub.2H.sub.4 (C1 basis): 100 ppm, C.sub.10H.sub.22/C.sub.7H.sub.8 (2.5:1 ratio, C1 basis): 190 ppm, NO: 180 ppm, O.sub.2: 10%, CO.sub.2: 10%, H.sub.2O: 10%; ramp rate: 20 C. per minute, space velocity: 50,000 l/hour. All core samples were aged in a tubular furnace for 16 hours, at 800 C., with 10% steam (H.sub.2O) in air.

[0265] For the samples listed in Table 7 (Examples 15-17), light-off results for HCHO, CO, HC (excluding-HCHO), and NO.sub.2/NO.sub.x performance at 200 C., are listed in Table 10. As the focus of this evaluation was on FICHO conversion, the conversion for the rest of HCs (excluding-HCHO) was listed here to show the impact of HCHO on the L/O of other HC components.

TABLE-US-00010 TABLE 10 Catalyst articles: Pt/Pd on various supports L/O for HC Single L/O for (excluding- L/O for NO.sub.2/ Example washcoat HCHO, at HCHO), at CO, at NO.sub.x, # layer T.sub.80, C. T.sub.80, C. T.sub.50, C. at 200 C. 15A (Ref- 1% 2:1 218 199 0.7 erence A) Pt/Pd on ZrO.sub.2 16 (Ref- 1% 2:1 208 197 0.7 erence B) Pt/Pd on La/ZrO.sub.2 17 1% 2:1 199 249 185 5.9 Pt/Pd on Zr/Al.sub.2O.sub.3

[0266] Example 17 (1% Pt/Pd on Zr/Al.sub.2O.sub.3) offers a better CO/HC and MHO L/O, along with a higher NO.sub.2/NO.sub.x performance value at 200 C., indicating that Zr itself might not be the best support, and Zr deposited on a high surface area alumina support provides a better overall performance. It can also be noted that the Zr supports cannot provide a HC.sub.T80 L/O below 300 C., the upper limit of the L/O protocol.

[0267] After adding 5% Mn onto various supports, the L/O results, as shown in Table 11, indicate that Mn is indeed an enhancer for the overall performance across the board (except for NO.sub.2/NO.sub.x performance at 200 C.), compared to the supports without Mn (Table 10). However, a comparison of NO.sub.2/NO.sub.x L/O performance on these supports in FIG. 6, shows that the sample with 1% 2:1 Pt/Pd and 5% Mn on Zr/Al.sub.2O.sub.3 offers the best NO.sub.2/NO.sub.x performance at T>210 C. Also, all the samples with non-zirconium supports (Examples 20, 21, and 22) offer better HC L/O performance. Except for the La/Zr (Reference D), all the inventive supports outperform the zirconium-oxide-only support in HCHO L/O conversion. While 5% Mn improves HC L/O by more than 20 C. for the Zr/Al.sub.2O.sub.3, it did not lift the zirconium-oxide-based supports to a HC.sub.T80 L/O below 300 C., as shown in Table 11.

TABLE-US-00011 TABLE 11 Catalyst articles: Pt/Pd on various supports with 5% Mn L/O for HC L/O for Exam- Single L/O for (non- CO, at NO.sub.2/ ple washcoat HCHO, at HCHO), at T.sub.50, NO.sub.x, at # layer T.sub.80, C. T.sub.80, C. C. 200 C. 18 (Ref- 1% 2:1 Pt/Pd 170 190 2.8 erence C) with 5% Mn on ZrO.sub.2 19 (Ref- 1% 2:1 Pt/Pd 117 198 0.3 erence D) with 5% Mn on La/ZrO.sub.2 20 1% 2:1 Pt/Pd 155 224 194 2.3 with 5% Mn on Zr/Al.sub.2O.sub.3 21 1% 2:1 Pt/Pd 155 241 179 4.8 with 5% Mn on La/Zr/ Al.sub.2O.sub.3 22 1% 2:1 Pt/Pd 137 243 178 0.2 with 5% Mn on Zr/CeO.sub.2

[0268] At a higher Mn loading (25% Mn on the supports), as shown in Table 12, all supports improved in HCHO L/O, and to a lesser degree, CO L/O as well. Improvement in HC L/O was observed for the Pt/Pd with 25% Mn on Zr/CeO.sub.2 support. While a greater than 25 C. improvement in HC L/O was observed for the Zr/CeO.sub.2 support, compared to 5% Mn samples

[0269] (Table 11), the additional 20% Mn onto the La/Zr/Al.sub.2O.sub.3 support did not improve the FICTso L/O, indicating that the Mn-/La ratio might have different optimum values for HCHO and HC conversions. Nonetheless, the greatest benefit of using the support in Example 21, is the gain in NO.sub.2/NO.sub.x values at low temperatures, as shown in FIG. 7 and Table 12. Accordingly, the inventive Mn on Zr/CeO.sub.2 support exhibited good HC/CO L/O and NO.sub.2/NOx performance in low temperatures, in addition to a comparable HCHO L/O performance to the La/Zr/Al.sub.2O.sub.3 support.

TABLE-US-00012 TABLE 12 Catalyst articles: Pt/Pd on various supports with 25% Mn L/O for HC L/O for Exam- Single L/O for (non- CO, at NO.sub.2/ ple washcoat HCHO, at HCHO), at T.sub.50, NO.sub.x, at # layer T.sub.80, C. T.sub.80, C. C. 200 C. 18 (Ref- 1% 2:1 Pt/Pd 148 246 186 2.2 erence E) with 25% Mn on ZrO.sub.2 19 (Ref- 1% 2:1 Pt/Pd 93 276 196 0.3 erence F) with 25% Mn on La/ZrO.sub.2 20 1% 2:1 Pt/Pd 120 251 176 4.3 with 25% Mn on La/Zr/ Al.sub.2O.sub.3 21 1% 2:1 Pt/Pd 128 217 168 9.0 with 25% Mn on Zr/CeO.sub.2

[0270] In addition to the supports listed above (Examples 15-22), several different supports, other than the Reference B (Example 16) were also evaluated in the powder form. The sample preparation process is similar to Example 2, except that the dopant and support were different detailed description of various powder samples in this new set of experiments is listed in Table 13, and all the supports were preformed (commercially available).

TABLE-US-00013 TABLE 13 Catalyst articles: 1% Pt/Pd (Pt/Pd = 2/1), on various supports Example # Single washcoat layer Support compositions 23 (Ref- 1% 2:1 Pt/Pd on La/ZrO.sub.2 La/ZrO.sub.2: about 9% La, erence E) 91% Zr 24 1% 2:1 Pt/Pd with 10% Y Y/ZrO.sub.2: about 10% Y, on ZrO.sub.2 90% Zr 25 1% 2:1 Pt/Pd with 10% Si Si/ZrO.sub.2: about 10% Si, on ZrO.sub.2 90% Zr 26 1% 2:1 Pt/Pd with 24% Mn Mn/ZrO.sub.2: about 24% Mn, on ZrO.sub.2 76% Zr 27 1% 2:1 Pt/Pd with 5% Si Si/TiO.sub.2: about 5% Si, on TiO.sub.2 95% Ti 28 1% 2:1 Pt/Pd with 5% Si Si/Al.sub.2O.sub.3: about 5% Si, on Al.sub.2O.sub.3 95% Al

[0271] The powder sample preparation and testing processes are the same as described in Example 15. The results are listed in Tables 14 to 17.

TABLE-US-00014 TABLE 14 HC/CO Light-Off (L/O) Temperatures and NO.sub.2 yield at 300 C. & 250 C. (fresh & aged samples) HC.sub.70 CO.sub.50 NO.sub.2 NO.sub.2 L/O, L/O, yield at yield at State Example # C. C. 300 C., % 250 C., % Fresh Example 23 230 174 33.7 10.2 (Ref) Example 24 225 173 42.8 17.3 Aged Example 23 265 213 4.4 2.0 (Ref) Example 24 253 200 15.4 4.8

[0272] From Table 14 and FIG. 8, the Y on ZrO.sub.2 support (inventive example 24) outperforms the La/ZrO.sub.2 in both CO/HC L/O and NO.sub.2 yield, either fresh or aged samples.

TABLE-US-00015 TABLE 15 HC/CO Light-Off (L/O) Temperatures and NO.sub.2 yield at 300 C. & 250 C. (fresh & aged samples) HC.sub.70 CO.sub.50 NO.sub.2 NO.sub.2 L/O, L/O, yield at yield at State Example # C. C. 300 C., % 250 C., % Fresh Example 23 230 174 33.7 10.2 (Ref) Example 25 223 175 57.0 28.2 Aged Example 23 265 213 4.4 2.0 (Ref) Example 25 264 210 9.9 2.4

[0273] From Table 15 and FIG. 9, the Si on ZrO.sub.7 support (inventive example 25) also outperforms the La/ZrO.sub.2 in both CO/HC L/O and NO.sub.2 yield, either fresh or aged samples.

TABLE-US-00016 TABLE 16 HC/CO Light-Off (L/O) Temperatures and NO.sub.2 yield at 300 C. & 250 C. (fresh & aged samples) HC.sub.70 CO.sub.50 NO.sub.2 NO.sub.2 L/O, L/O, yield at yield at State Example # C. C. 300 C., % 250 C., % Fresh Example 23 230 174 33.7 10.2 (Ref) Example 26 222 168 55.8 27.2 Aged Example 23 265 213 4.4 2.0 (Ref) Example 26 245 208 32.0 9.3

[0274] From Table 16 and FIG. 10, the Mn on ZrO2 support (inventive example 26) outperforms the La/ZrO.sub.2 in both CO/FIC L/O and NO.sub.2 yield, and especially in NO.sub.2 yield. either fresh or aged samples. The inventive example 26 sample also provides a very good NO.sub.2 performance stability, between fresh and aged samples.

TABLE-US-00017 TABLE 17 HC/CO Light-Off (L/O) Temperatures and NO.sub.2 yield at 300 C. & 250 C. (fresh & aged samples) HC.sub.70 CO.sub.50 NO.sub.2 NO.sub.2 L/O, L/O, yield at yield at State Example # C. C. 300 C., % 250 C., % Fresh Example 23 230 174 33.7 10.2 (Ref) Example 27 215 171 65.9 41.2 Aged Example 23 265 213 4.4 2.0 (Ref) Example 27 252 208 25.2 4.6

[0275] From Table 17 and FIG. 11, the Si on TiO.sub.2 support (inventive example 27) outperforms the La/ZrO.sub.2 in both CO/HC L/O and NO.sub.2 yield as well, and especially in NO.sub.2 yield, either fresh or aged samples.

TABLE-US-00018 TABLE 18 HC/CO Light-Off (L/O) Temperatures and NO.sub.2 yield at 300 C. & 250 C. (fresh & aged samples) HC.sub.70 CO.sub.50 NO.sub.2 NO.sub.2 L/O, L/O, yield at yield at State Example # C. C. 300 C., % 250 C., % Fresh Example 23 230 174 33.7 10.2 (Ref) Example 28 224 169 47.9 20.9 Aged Example 23 265 213 4.4 2.0 (Ref) Example 28 253 199 22.0 2.4

[0276] Again, from Table 18 and FIG. 12, the Si on Al.sub.2O.sub.3 support (inventive example 28) outperforms the La/ZrO.sub.2 in both CO/HC L/O and NO.sub.2 yield, either fresh or aged samples.