The present disclosure provides catalyst compositions for NOx conversion and catalytic articles incorporating such catalyst compositions. Certain catalyst compositions include a zeolite with a silica-to-alumina ratio from 5 to 20 and sufficient Cu exchanged into cation sites of the zeolite such that the zeolite has a Cu/Al ratio of 0.1 to 0.5 and a CuO loading of 1 to 15 wt. %; and a copper trapping component in a concentration in the range of 1 to 20 wt. %, the copper trapping component including a plurality of particles having a particle size of about 0.5 to 20 microns. Certain catalyst compositions include, as the copper trapping component, alumina present as a plurality of alumina particles with a D.sub.90 particle size distribution in the range of 0.5 microns to 20 microns.

The present invention relates to a three-way catalyst (TWC) for treatment of exhaust gases from internal combustion engines operated with a predominantly stoichiometric air/fuel ratio, so called spark ignited engines.

A device that includes a conduit, a first window, a second window, a first catalyzed layer, a second catalyzed layer, an optical source, and an optical detector is disclosed. The conduit may be configured to receive an exhaust gas. The first catalyzed layer may be disposed on the first window and the second catalyzed layer may be disposed on the second window. The first catalyzed layer and the second catalyzed layer may be configured to cause a reaction with soot in the exhaust gas at an activation temperature to reduce accumulation of the soot on the first window and the second window. The optical source may be configured to emit a beam of light into the conduit through the first window. The optical detector may be configured to receive at least a portion of the beam of light through the second window.

A Ce—Zr composite oxide contains cerium and zirconium, wherein an uneven distribution ratio of cerium atoms is 1.80 or less. A method for producing a Ce—Zr composite oxide includes an acid treatment step of bringing at least one selected from the group consisting of sulfuric acid, nitric acid, and hydrochloric acid, in an amount of 4 to 28 parts by mass with respect to 100 parts by mass of the raw material composite oxide, into contact with the surface of a raw material composite oxide containing cerium and zirconium, and a calcination step of calcining the treated composite oxide obtained in the acid treatment step at 400 to 1200° C. for 5 to 300 minutes.

The present invention relates to a three-way catalyst (TWC) for treatment of exhaust gases from internal combustion engines operated with a predominantly stoichiometric air/fuel ratio, so called spark ignited engines.

A composite oxidation catalyst (18, 20) for use in an exhaust system for treating an exhaust gas produced by a vehicular compression ignition internal combustion engine (30) and upstream of a particulate matter filter (44, 50) in the exhaust system comprises a substrate (5) having a total length L and a longitudinal axis and having a substrate surface extending axially between a first substrate end (I) and a second substrate end (O); and three or more catalyst washcoat zones (1, 2, 3; or 1, 2, 3, 4) arranged axially in series on and along the substrate surface, wherein a first catalyst washcoat zone (1) having a length L.sub.1, wherein L.sub.1<L, is defined at one end by the first substrate end (I) and at a second end by a first end (19, 21) of a second catalyst washcoat zone (2) having a length L.sub.2, wherein L.sub.2<L, wherein the first catalyst washcoat zone (1) comprises a first refractory metal oxide support material and two or more platinum group metal components supported thereon comprising both platinum and palladium at a weight ratio of platinum to palladium of ≥1; the second catalyst washcoat zone (2) comprises a second refractory metal oxide support material and one or more platinum group metal components supported thereon; and a third catalyst washcoat zone (3) comprising a third refractory metal oxide support material and one or more platinum group metal components supported thereon is defined at a second end thereof by the second substrate end (O), wherein a total platinum group metal loading in the first catalyst washcoat zone (1) defined in grams of platinum group metal per cubic foot of substrate volume (g/l) (g/ft.sup.3) is greater than a total platinum group metal loading in the second catalyst washcoat zone (2), wherein a total platinum group metal loading in the third catalyst washcoat zone (3) defined in grams of platinum group metal per cubic foot of substrate volume (g/l) (g/ft.sup.3) is less than the total platinum group metal loading in the second catalyst washcoat zone (2) and wherein the first catalyst washcoat zone (1) comprises one or more first alkaline earth metal components supported on the first refractory metal oxide support material.

Disclosed herein are emission treatment systems, articles, and methods for selectively reducing NOx compounds. The systems include a hydrogen generator, a hydrogen selective catalytic reduction (H.sub.2-SCR) article, and one or more of a diesel oxidation catalyst (DOC) and/or a lean NOx trap (LNT) and/or a low temperature NOx adsorber (LTNA). Certain articles may comprise a zone coated substrate and/or a layered coated substrate and/or an intermingled coated substrate of one or more of the H.sub.2-SCR and/or DOC and/or LNT and/or LTNA catalytic compositions.

The present invention relates to a three-way catalyst (TWC) for treatment of exhaust gases from internal combustion engines operated with a predominantly stoichiometric air/fuel ratio, so called spark ignited engines.

A gasoline engine exhaust gas purification catalyst for purifying exhaust gas emitted from a gasoline engine includes a precious metal, alumina, and a ceria/zirconia composite oxide supported on a three-dimensional structure, and has pores having a peak 1 at a pore size of not less than 0.001 μm and not greater than 0.05 μm, pores having a peak 2 at a pore size of not less than 2.5 μm and not greater than 5.0 μm, and pores having a peak 3 at a different pore size than the above pore sizes in a pore size distribution measured by mercury intrusion method, wherein the pore volume of the pores having the peak 3 is greater than 1.4% of the total pore volume. A production method for the catalyst, and an exhaust gas purification method using the catalyst are also described.

Disclosed are a honeycomb-like homo-type heterojunction carbon nitride composite material and a preparation method thereof, and an application of the honeycomb-like homo-type heterojunction carbon nitride composite material in catalytic treatment of waste gas. The preparation method includes the following steps: with two different carbon nitride precursors namely urea and thiourea as raw materials, weighing certain amounts of the urea and the thiourea, adding the urea and the thiourea into a crucible, adding a certain amount of ultrapure water, placing the crucible in a muffle furnace, and carrying out calcination molding. The honeycomb-like homo-type heterojunction carbon nitride prepared by the one-step method has good photocatalytic effect to catalytic degradation of NO; meanwhile, the honeycomb-like homo-type heterojunction carbon nitride composite material has the advantages of rich and easily-available production raw materials, good stability, reusability, etc., and has application prospects in the field of treatment of NO in the air.