It is an object to provide a catalyst that can effectively purify exhaust gas, in particular, carbon monoxide (CO) in exhaust gas, emitted from a diesel engine, a production method therefor, and an exhaust gas purification method using the same. A diesel engine exhaust gas purification catalyst for purifying exhaust gas emitted from a diesel engine of the present invention comprises a precious metal and alumina and/or zeolite supported on a three-dimensional structure, and has peaks for not less than three different pore sizes in a pore size distribution measured by the mercury intrusion method, wherein one of the peaks is a peak 2 at a pore size of not less than 0.3 μm and less than 1.0 μm, and the pore volume of the peak 2 being greater than 3.1% of the total pore volume.

The present disclosure is directed to a low temperature carbon monoxide (LT-CO) oxidation catalyst composition for abatement of exhaust gas emissions from a lean burn engine. The LT-CO oxidation catalyst composition includes an oxygen storage component (OSC), a first platinum group metal (PGM) component, and a promoter metal, wherein the OSC is impregnated with the first PGM component and the promoter metal and the LT-CO oxidation catalyst composition is effective for oxidizing carbon monoxide (CO) and hydrocarbons (HC) under cold start conditions. Further provided are catalytic articles including the LT-CO oxidation catalyst composition, which may optionally further include a diesel oxidation catalyst (DOC) composition (giving an LT-CO/DOC article). Further provided is an exhaust gas treatment system including such catalytic articles, and methods for reducing a HC or CO level in an exhaust gas stream using such catalytic articles.

This invention relates to methods and systems for reducing the concentration of SOx and/or NOx in gas streams.

The present disclosure is directed to a method for treating a gaseous exhaust stream containing nitrogen oxides (NO.sub.x) from a diesel or lean-burn gasoline engine following a cold-start of the engine The method involves contact of the gaseous exhaust stream with at least a low temperature NO.sub.x adsorber (LT-NA) component. The LT-NA component includes a rare earth metal component, a platinum group metal (PGM) component, and a dopant. The present disclosure is also directed to a method of modulating a NO.sub.x adsorption/desorption profile of an LT-NA composition, a NO.sub.x desorption temperature range of an LT-NA composition, or both.

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.

When the porous ceramic structure contains Co together with Fe or Mn, the Co content is higher than or equal to 0.1 mass % and lower than or equal to 3.0 mass % in terms of Co.sub.3O.sub.4, and when the porous ceramic structure contains Co without containing Fe and Mn, the Co content is higher than or equal to 0.2 mass % and lower than or equal to 6.0 mass % in terms of Co.sub.3O.sub.4. The Ce content is higher than or equal to 0.1 mass % and lower than or equal to 10 mass % in terms of CeO.sub.2. The Fe/Mn/Co ratio is higher than or equal to 0.8 and lower than or equal to 9.5. The porous ceramic structure contains more than or equal to 0.03 percent and less than or equal to 2.5 percent by mass of Zn in terms of ZnO.

The invention relates to a selective ammonia oxidation catalysts comprising a platinum group metal and a support comprising TiO2 doped with 0-10% by weight of SiO.sub.2, WO.sub.3, ZrO.sub.2, Y.sub.2O.sub.3, La.sub.2O.sub.3, or a mixture thereof. The invention further comprises methods for the manufacture of the selective ammonia oxidation catalysts, and integrated catalyst systems comprising the selective ammonia oxidation catalysts for treating an exhaust gas stream.

A three-way catalyst article, and its use in an exhaust system for internal combustion engines, is disclosed. The catalyst article for treating exhaust gas comprising: a substrate comprising an inlet end and an outlet end with an axial length L; a first catalytic region comprising a first platinum group metal (PGM) component supported on a first PGM support material, wherein the first PGM component comprises rhodium (Rh) and platinum (Pt); and wherein Pt and Rh has a weight ratio of at least 1:10.

An engine exhaust aftertreatment system having an organization and arrangement of certain selected components which achieve significant catalytic reduction of the known NOx pollutants (NO and NO.sub.2) in tailpipe-out exhaust, while also achieving significant catalytic reduction of sulfate pollutants in tailpipe-out exhaust.