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.

Metal oxide nanoarrays, such as titanium oxide nanoarrays, having a platinum group metal dispersed thereon and methods of making such nanoarrays are described. The platinum group metal can be dispersed on the metal oxide nanoarray as single atoms. The nanoarrays can be used to catalyze oxidation of combustion exhaust.

Catalyst material composed of a sodium incorporated cerium-zirconium based mixed oxide catalyst material, such as Ce—Zr/Al.sub.2O.sub.3, for oxygen storage capacity applications. The sodium incorporated cerium-zirconium based mixed oxide catalyst material is synthesized by co-precipitation techniques using sodium carbonate as the precipitating agent and exhibits a high oxygen storage capacity.

The present invention relates to a catalyst washcoat composition comprising a slurry comprising at least one platinum group metal and/or at least one non-platinum group metal supported on at least one support; and at least one pore forming agent having a particle size ranging from 100 nm to 5.0 μm, wherein the pore forming agent is selected from carbon nano-tubes, carbon nano-fibres, activated carbon, resins, cellulose powder, and polymer spheres. The present invention also provides a catalyst article for capturing particulate matter of size ranging from 1.0 nm to 100 μm, said article comprising the catalyst washcoat deposited on a substrate and calcined to form pores of which 50%-100% have a pore size ranging from 100 nm to 5.0 μm.

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 %.

A method of manufacturing a catalyst article, the method comprising: providing a complex of a polyphenol and a PGM, the polyphenol comprising an ester functional group, the PGM comprising palladium; 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.

A method of manufacturing a catalyst article, the method comprising: providing a complex of a polyphenol and a PGM, the PGM comprising rhodium and/or platinum, the polyphenol comprising an ester functional group; 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, in particular a particulate filter for use in an emission treatment system of an internal combustion engine. The particulate filter provides an advantageous combination of low back pressure and high fresh filtration efficiency.

A process for the production of a catalyst comprising the steps of: dissolving the requisite quantities of copper nitrate and nickel nitrate in de-ionised water to provide a sub-0.30 molar aqueous solution of copper nitrate and nickel nitrate together in the ratio required; providing an ammoniacal solution by adding concentrated aqueous solution of ammonia in a quantity equal to between six and ten times the quantity required to realise both a 1:6 molar ratio for Cu.sup.2+ to ammonia and a 1:6 molar ratio for Ni.sup.2+ to ammonia; loading gamma alumina with 1 to 30% w/w of copper and nickel in a weight ratio of nickel to copper of 1:5 to 2:1 by suspending the requisite quantity of gamma alumina in said ammoniacal solution to achieve the required loading of copper and nickel; stirring the resulting gamma alumina suspension for at least 4 h at room temperature; then the volatile components evaporate under ambient conditions leaving dry loaded gamma alumina, which is calcined at a temperature of at least 260° C. for at least 30 min with a constant heating up rate; a catalyst or catalyst mixture, the catalyst or each catalyst in the catalyst mixture being obtainable by the above-mentioned process; and the use of the catalyst or catalyst mixture for the conversion of exhaust gases from an internal combustion engine into carbon dioxide, water and nitrogen.