An object of the present invention is to provide an exhaust gas purification catalyst having improved exhaust gas purifying performance (in particular, improved NOx purifying performance) at low to medium temperature, and, in order to achieve the object, the present invention provides an exhaust gas purification catalyst (10A) including: a substrate (20); and a catalyst layer (30 or 40) formed on the substrate (20), wherein the catalyst layer (30 or 40) contains rhodium element, phosphorus element and a rare earth element other than cerium element, wherein a ratio of a mass of the phosphorus element contained in the catalyst layer (30 or 40) to the mass of the rhodium element contained in the catalyst layer (30 or 40) is from 1 to 10, and wherein a ratio of a mass of the rare earth element other than cerium element in terms of an oxide thereof contained in the catalyst layer (30 or 40) to the mass of the rhodium element contained in the catalyst layer (30 or 40) is from 1 to 5.

A method of manufacturing a catalyst article, the method comprising: providing a complex of a humic acid or derivative thereof, and a PGM; providing a support material; applying the complex to the support material to form a loaded support material; disposing the loaded support material on a substrate; and heating the loaded support material to form nanoparticles of the PGM on the support material.

The present 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 the surfaces O.sub.E and O.sub.A, respectively, and wherein the channels E are closed at the second end and the channels A are closed at the first end. The invention is characterized in that the coating Y is located in the channels E on the surfaces O.sub.E and the coating Z is located in the channels A on the surfaces O.sub.A.

A method of manufacturing a catalyst article, the method comprising: providing an anionic complex comprising a PGM and a carboxylate ion; providing a support material; applying the anionic complex to the support material to form a loaded support material; disposing the loaded support material on a substrate; and heating the loaded support material to form nanoparticles of the PGM on the support material.

The present disclosure provides an exhaust gas purification catalyst improved in OSC performance while maintaining an exhaust gas purification performance, which comprises a substrate and at least one catalyst layer formed on the substrate, wherein an uppermost catalyst layer contains a catalyst metal, a first OSC material having a pyrochlore structure, and a second OSC material having a higher oxygen storage/release rate than the first OSC material, wherein the uppermost catalyst layer consists of an upstream catalyst layer and a downstream catalyst layer, and wherein a proportion of a mass of the second OSC material based on a total mass of the first OSC material and the second OSC material is in a specific range in each of the upstream catalyst layer and the downstream catalyst layer.

Subject of the invention is an exhaust gas purification system for a gasoline engine, comprising in consecutive order the following devices: a first three-way-catalyst (TWC1), a gasoline particulate filter (GPF) and a second three-way-catalyst (TWC2), wherein the oxygen storage capacity (OSC) of the TWC2 is greater than the OSC of the GPF, wherein the OSC is determined in mg/l of the volume of the device. The invention also relates to methods in which the system is used and uses of the system.

An exhaust gas purification catalyst apparatus has a honeycomb base material and a catalyst noble metal supported by the honeycomb base material, wherein: the honeycomb base material contains ceria-zirconia composite oxide particles as one of the constituent materials, is of a wall flow type, and includes inlet-side cells and outlet-side cells demarcated by porous partition walls; the catalyst noble metal is supported in inlet-side support regions and outlet-side support regions; each of the inlet-side support regions is formed with a specific length from the exhaust gas flow upstream end; the catalyst noble metal 70% support depth is not greater than 50% of the thickness of the porous partition walls; each of the outlet-side support regions is formed with a specific length from the exhaust gas flow downstream end; and the catalyst noble metal 70% support depth is greater than 50% of the thickness of the porous partition walls.

An exhaust gas purification catalyst including particles of a catalyst metal supported on secondary particles of an inorganic oxide, wherein when scanning transmission electron microscope-energy dispersive X-ray line analysis is performed from a surface of the secondary particles toward a center thereof, a support density of the catalyst metal on a surface side of the secondary particles is greater than the support density of the catalyst metal in a center part of the secondary particles.

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 the surfaces of the partition walls that each face the inflow-side cell and/or the 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 greater than 10% to 30% or less based on the apparent area of the catalyst portion present on the partition wall. The content of zirconium element in terms of oxide (amount of ZrO2) in the catalyst portions is from 35 mass % to 85 mass %.

There is provided an exhaust gas purification device that shows a high HC removal performance under a condition in which a rich air-fuel mixture is introduced. The exhaust gas purification device includes a substrate, a first catalyst layer, and a second catalyst layer. The substrate includes an upstream end and a downstream end. The first catalyst layer is disposed on a surface of the partition wall in an upstream region including the upstream end of the substrate. The second catalyst layer is disposed inside the partition wall in a downstream region including the downstream end of the substrate. The first catalyst layer contains a first metal catalyst and alumina-zirconia composite oxide. The second catalyst layer contains a second metal catalyst.