The present invention provides a catalyst composition comprising a) platinum; b) rhodium; and c) a ceria-alumina composite, a zirconia composite or a mixture thereof, wherein platinum is supported on the ceria-alumina composite, zirconia composite or mixture thereof, wherein rhodium is supported on the ceria-alumina composite, zirconia composite or mixture thereof, wherein CeO.sub.2 in the ceria alumina composite is 1.0 to 50 wt. %, based on the total weight of the ceria-alumina composite, wherein the amount of ZrO.sub.2 in the zirconia composite is 50 to 99 wt. %, based on the total weight of the zirconia composite. The present invention also provides a catalytic article comprising the catalyst composition and its preparation.

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.

The present disclosure provides an exhaust gas purifying catalyst that may exhibit high purification performance both in a low temperature state immediately after an engine is started and during a high-load operation. The exhaust gas purifying catalyst disclosed herein contains at least one type of noble metal purifying exhaust gas, and includes a substrate, and a catalyst coat layer formed on a surface of the substrate. The catalyst coat layer is formed to have a stack structure including a lower layer provided on the substrate and an upper layer provided on the lower layer. The lower layer contains a noble metal and an oxide having an oxygen storage capacity. A noble metal-containing surface layer portion containing a noble metal is formed in at least a part of a surface portion of the upper layer. The upper layer does not contain an oxide having the oxygen storage capacity.

A three-way catalyst for reduced palladium loading is provided. The catalyst includes an inert substrate and a palladium catalyst material coating the substrate. The palladium catalyst material includes a support material formed from one of 10% CeO.sub.2/Al.sub.2O.sub.3, 20% CeO.sub.2—Al.sub.2O.sub.3 (20CeAlOy), 30% CeO.sub.2—Al.sub.2O.sub.3 (30CeAlOy), Al.sub.2O.sub.3, and MOx-Al.sub.2O.sub.3, wherein M is one of copper, iron, manganese, titanium, zirconium, magnesium, strontium, and barium. The palladium catalyst material includes a layer of CeO.sub.2 material disposed upon the support material, wherein the layer of CeO.sub.2 material is dispersed on a surface of the support material. The palladium catalyst material includes an active component including a layer of praseodymium oxide particles dispersed across the surface of the layer of CeO.sub.2 material and a layer of palladium particles disposed upon and dispersed across the surface of the layer of CeO.sub.2 material at locations each corresponding to a respective location of each of the praseodymium particles.

An exhaust system includes a light-off catalyst, an exhaust system component, and at least one H.sub.2O trap. The exhaust system component is upstream from the light-off catalyst and includes catalyst material, the catalyst material configured to store hydrocarbons during a period when the light-off catalyst is warming up to a light-off temperature. The at least one H.sub.2O trap is at or upstream from the exhaust system component and is configured to perform H.sub.2O adsorption and desorption to increase a length of time for the exhaust system component to reach a hydrocarbon release temperature and prevent the exhaust system component from reaching the hydrocarbon release temperature prior to the light-off catalyst reaching the light-off temperature.

A three-way catalyst for reduced palladium loading is provided. The catalyst includes an inert substrate and a palladium catalyst material coating the substrate. The palladium catalyst material includes a support material formed from one of 10% CeO.sub.2/Al.sub.2O.sub.3, 20% CeO.sub.2—Al.sub.2O.sub.3 (20CeAlOy), 30% CeO.sub.2—Al.sub.2O.sub.3 (30CeAlOy), Al.sub.2O.sub.3, and MOx-Al.sub.2O.sub.3, wherein M is one of copper, iron, manganese, titanium, zirconium, magnesium, strontium, and barium. The palladium catalyst material includes a layer of CeO.sub.2 material disposed upon the support material, wherein the layer of CeO.sub.2 material is dispersed on a surface of the support material. The palladium catalyst material includes an active component including a layer of praseodymium oxide particles dispersed across the surface of the layer of CeO.sub.2 material and a layer of palladium particles disposed upon and dispersed across the surface of the layer of CeO.sub.2 material at locations each corresponding to a respective location of each of the praseodymium particles.

This invention relates to a novel palladium catalyst for the substantially complete oxidative removal of methane from exhaust streams at low operating temperatures compared to other current palladium catalysts and to methods of preparing the catalyst. Use of the catalyst to remove methane from vehicle exhaust streams, crude oil production and processing exhaust streams, petroleum refining exhaust streams and natural gas production and processing exhaust streams.

A catalyst article is provided including a substrate including a plurality of passageways, and further including a first and a second oxidation region including a first and a second subset of said plurality of passageways. A first catalyst composition is coating at least a portion of each passageway of the first oxidation region and positioned as a sole PGM-containing catalyst layer, or a zoned portion thereof, or as a top PGM-containing catalyst layer, or a zoned portion thereof, in the first oxidation region. A second catalyst composition is coating at least a portion of each passageway of the second oxidation region and positioned as a sole PGM-containing catalyst layer, or a zoned portion thereof, or as a top PGM-containing catalyst layer, or a zoned portion thereof, in the second oxidation region. The Pt:Pd weight ratio is greater in the first catalyst composition than in the second catalyst composition.

The present invention provides a chemically stable catalyst for methane removal that exhibits excellent methane removal performance. The catalyst material for methane removal 30 of the invention includes a carrier 32 made of alumina and a catalyst 34 made of at least one of palladium and palladium oxide and carried directly on the carrier 32. With an exhaust gas purification catalyst test piece using this catalyst material for methane removal 30, a 50% methane removal temperature, which is an environmental temperature at which a methane removal rate reaches 50%, is not more than 347° C., based on the methane removal rate at 25° C. Furthermore, a specific surface area of the carrier 32 is preferably not more than 80 m.sup.2/g.

Provided are an exhaust gas purifying catalyst structure that inhibits foil elongation and improves structural durability and a production method therefor. The exhaust gas purifying catalyst structure has a metal support configured by using an mantle and a metal foil provided in the mantle and forming an exhaust gas flow path, and a catalyst layer provided on a surface forming the flow path of the metal foil, wherein the catalyst layer contains a noble metal, an OSC material containing cerium and a rare earth element other than cerium (non-Ce rare earth element), and alumina, and a content of the non-Ce rare earth element with respect to 100% by mass of the catalyst layer is 2.52% by mass or more and 4.62% by mass or less in terms of an oxide.