The present invention relates to a particulate filter for removing particles, carbon monoxide, hydrocarbons and nitrogen oxides from the exhaust gas from internal combustion engines operated with a stoichiometric air-fuel mixture. Two coatings Y and Z are located in the porous walls and are present from the first end of the wall-flow filter over the entire length L of the particulate filter. Both contain active alumina, at least one cerium-zirconium-rare earth metal mixed oxide and at least one platinum group metal.

The invention relates to a particulate filter which comprises a wall flow filter of length L and two catalytically active coatings Y and Z, wherein the wall flow filter comprises channels E and A that extend in parallel between a first and a second end of the wall flow filter and are separated by porous walls which form surfaces OE and OA, respectively, and wherein the channels E are closed at the second end and the channels A are closed at the first end, and the coatings Y and Z have the same oxygen storage components and the same carrier materials for noble metals. The invention is characterised in that the coating Y is located in the channels E on the surfaces OE and the coating Z is located in the channels Aon the surfaces OA.

An exhaust gas purification catalyst provides excellent removal performance of methane, which is chemically stable. Exhaust gas purification catalyst includes a substrate that divides cells through which an exhaust gas flows and a catalyst layer that is provided on a surface of the substrate. The catalyst layer includes a palladium layer containing palladium that extends from a first end part which is an end part on the side into which an exhaust gas in the cells flows to a second end part which is an end part on the side from which an exhaust gas flows out, a platinum layer containing platinum that extends from the second end part to the first end part, and a rhodium layer containing rhodium that is laminated with both the palladium layer and the platinum layer.

An exhaust gas purification catalyst device having a substrate, a first catalyst coating layer on the substrate, and a second catalyst coating layer on the first catalyst coating layer. The first catalyst coating layer includes inorganic oxide particles, palladium carried on the inorganic oxide particles, and a barium compound. The second catalyst coating layer includes alumina particles and rhodium carried by the alumina particles. The ratio (M.sub.Ba/M.sub.Rh) between the mass (M.sub.Ba) of barium in the first catalyst coating layer and the mass (M.sub.Rh) of rhodium in the second catalyst coating layer is 5.0-60.0 inclusive.

The invention relates to a particulate filter which comprises a wall flow filter of length L and two different catalytically active coatings Y and Z, wherein the wall flow filter comprises channels E and A that extend in parallel between a first and a second end of the wall flow filter and are separated by porous walls which form surfaces OE and OA, respectively, and the channels E are closed at the second end and the channels A are closed at the first end. The invention is characterised in that the coating Y is located in the channels E on the surfaces OE and the coating Z is located in the channels A on the surfaces OA.

A substrate (11) of an exhaust gas purification catalyst (10) includes inflow-side cells (21), outflow-side cells (22), and porous partition walls (23) each separating the inflow-side cell and the outflow-side cell. Catalyst portions (14, 15) are provided on surfaces of the partition walls that each face the inflow-side cell and/or surfaces of the partition walls that each face the outflow-side cell. In a cross section vertical to an exhaust gas flow direction, the percentage of the total area of voids, each void satisfying the expression L/{2(πS).sup.1/2}≤1.1, wherein L is the perimeter of the void in the cross section and S is the area of the void in the cross section, is from 3 to 10% based on the apparent area of the catalyst portion present on the partition wall.

The presently claimed invention provides a tri-metallic layered catalytic article comprising: a) a top layer comprising platinum supported on at least one of an oxygen storage component, zirconia component and an alumina component, and rhodium supported on an oxygen storage component; b) a bottom layer comprising a front zone and a rear zone, said front zone comprising palladium supported on an oxygen storage component and an alumina component, and the rear zone comprises platinum supported on at least one of an alumina component, a ceria component, and an oxygen storage component; and c) a substrate, wherein the weight ratio of palladium to platinum is in the range of 1.0:0.4 to 1.0:2.0.

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.

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 provides a 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 support material particles; at least some of the support material particles are rhodium-supporting support material particles having rhodium supported thereon at a concentration of from 0.001 to 3.5 wt. %, based on the weight of the rhodium-supporting support material particle; and the rhodium is present at a loading of up to 20 g/ft.sup.3 relative to the first catalytic region.