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 platinum-group metal concentration (PGM) of the GPF is at least 40% greater than the PGM of the TWC2, wherein the PGM is determined in g/ft3 of the volume of the device,

The invention also relates to methods in which the system is used and uses of the system.

A process for removing hydrocarbons from a feed stream containing hydrocarbons includes introducing ozone to the feed stream to produce an ozone doped stream containing ozone and hydrocarbons, and contacting the ozone doped stream with a supported metal catalyst at a temperature of from 100° C. to 300° C. to produce a treated stream, wherein the supported metal catalyst comprises iron supported on a support selected from aluminosilicates, silica-aluminas, silicates and aluminas. A process for removing NOx from a feed stream containing NOx, and an apparatus for removing hydrocarbons and/or NOx from a feed stream containing hydrocarbons and/or NOx are also provided.

Provided is an exhaust gas purification catalyst that suppresses phosphorus poisoning and improves long-term durability. The exhaust gas purification catalyst includes a phosphorus collection layer and a catalyst layer containing at least one precious metal element MP selected from the group consisting of Pt, Pd, and Rh, wherein the phosphorus collection layer is arranged on the upper layer side and/or the upstream side with respect to the catalyst layer; the phosphorus collection layer contains a composite oxide containing Al and an alkaline earth metal element M.sup.a that includes Mg and that may include at least one selected from the group consisting of Ca, Sr, and Ba, and having a cubic spinel structure belonging to the space group Fd-3m; the composite oxide has a M.sup.a/A1 molar ratio in a range of 0.02 or more and 0.60 or less; and the composite oxide has a peak derived from the cubic spinel structure belonging to the space group Fd-3m of the composite oxide between a diffraction angle 2θxm.sup.ao that is a position of a peak derived from an alkaline earth metal oxide M.sup.aO and a diffraction angle 2θx.sub.Al203 that is a position of a peak derived from an aluminum oxide Al.sub.2O.sub.3 in an X-ray diffraction spectrum.

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 porous walls.

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 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 ZrO.sub.2) in the catalyst portions is from 35 mass % to 85 mass %.

A particulate filter disclosed herein includes a wall-flow structure substrate 10 and a wash coat layer 20 held inside a partition 16 of the substrate 10. The wash coat layer 20 includes an inlet layer 22 formed to have predetermined length L.sub.A and thickness T.sub.A from near an end thereof on an exhaust gas inflow side X1, and an outlet layer 24 formed to have predetermined length L.sub.B and thickness T.sub.B from near an end thereof on an exhaust gas outflow side X2. The inlet layer 22 and the outlet layer 24 partially overlap each other. In the particulate filter disclosed herein, the inlet layer 22 contains a precious metal catalyst, while the outlet layer 24 contains substantially no precious metal catalyst. The length L.sub.A of the inlet layer is 50% or more and 75% or less of a total length L of the partition 16. Thus, the particulate filter is capable of achieving both PM collection performance and pressure-drop reduction performance at high levels.

A catalyst article for treating exhaust gas comprising: a substrate comprising an inlet end, an outlet end with an axial length L; a first catalytic region beginning at the inlet end and extending for less than the axial length L, wherein the first catalytic region comprises a first platinum group metal (PGM) component, a first inorganic oxide, and an optional first oxygen storage capacity (OSC) material; a second catalytic region beginning at the outlet end and extending for less than the axial length L, wherein the second catalytic region comprises a second PGM component, an optional second inorganic oxide, and a second OSC material; and a third catalytic region; wherein the weight ratio of the first inorganic oxide to the optional first OSC material is greater than 1:1.

The present disclosures provides a catalyst composition comprising a mixed oxide support material and a platinum group metal supported on the mixed oxide support material, the mixed oxide support material comprising a solid solution mixed oxide having the formula Ce.sub.wZr.sub.xSn.sub.yM.sub.zO.sub.a, wherein: 0.05≤w≤0.90; 0.05≤x≤0.90; 0.001≤y≤0.25; 0.001≤z≤0.60; w+x+y+z=1.00; 1.0≤a≤2.0; and M is an element selected from one or more of sodium, potassium, rubidium, caesium, magnesium, calcium, strontium, barium, scandium, yttrium, titanium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, technetium, rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, aluminium, gallium, thallium, silicon, germanium, lead, bismuth, lanthanum, praseodymium, neodymium, samarium, europium, gadolinium, terbium, erbium, lutetium, dysprosium, holmium, thulium and ytterbium.

To provide an exhaust gas purification filter having a high capability of collecting particulate matter. The exhaust gas purification filter includes a filter base material having a wall flow structure and an exhaust gas purification catalyst. A wash coating amount of the exhaust gas purification catalyst ranges from 60 to 110 g/L or less. When the exhaust gas purification filter is divided into an upstream part, a middle part, and a downstream part, and average values of catalyst area ratios of the exhaust gas purification catalyst supported by surfaces of the partition walls are acquired at predetermined locations in cells on an inflow side and cells on an outflow side, a minimum value, among the average values, is 28% or greater. A maximum value, among sizes of pores in the partition walls after the exhaust gas purification catalyst is supported, is 14.6 μm or less.