[Problem] Provided is an exhaust gas purification catalyst capable of exhibiting even higher exhaust gas purification performance without impairing Pd catalytic activity, and an exhaust gas purification system using the exhaust gas purification catalyst.

[Solution] Provided is an exhaust gas purification catalyst comprising a substrate and a catalyst layer provided on the substrate, said catalyst having a first section located upstream along a flow direction of the exhaust gas and a second section located downstream from the first section; the catalyst layer in the first section comprises a first catalyst layer comprising palladium and a second catalyst layer comprising rhodium and covering the first catalyst layer, wherein a pore volume proportion is 12% or more and less than 18% wherein the pore volume proportion is a proportion of a total volume of the pores, which have a pore diameter of 0.06 μm to 30.0 μm as measured by mercury press-in method and existing in the substrate and the catalyst layer in the first section to a volume of a entire first section; and a wash coat amount is 100 g/L to 190 g/L, wherein a wash coat amount is a mass per unit volume of the catalyst layer in the first section to the volume of the substrate existing in the first section.

An exhaust-gas purification catalyst that contains a perovskite-type composite oxide composed of at least Ba, Zr, Y, and Pd.

The present invention provides catalyst article, and its use in an exhaust system for internal combustion engines, is disclosed. The catalyst article catalyst article comprises: a substrate which is a wall-flow filter having an inlet end and an outlet end and an axial length L therebetween, a plurality of inlet channels extending from the inlet end and a plurality of outlet channels extending from the outlet end, wherein the plurality of inlet channels comprise a first catalyst composition extending from the inlet or outlet end for at least 50% of L and the plurality of outlet channels comprise a second catalyst composition extending from the outlet or inlet end for at least 50% of L, wherein the first and second catalyst compositions overlap by at most 80% of L, and wherein the first and second catalyst compositions each independently comprise a particulate oxygen storage component (OSC) having a first D90 and a particulate inorganic oxide having a second D90 and: i) the first D90 is less than 1 micron and the second D90 is from 1 to 20 microns; or ii) the second D90 is less than 1 micron and the first D90 is from 1 to 20 microns.

An exhaust gas purification system for a gasoline engine is described the system 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 GPF is greater than the OSC of the TWC1, wherein the OSC is determined in mg/l of the volume of the device.

Provided is a particulate filter in which a PM collection rate is stably increased. The particulate filter according to the present invention includes a substrate 10 having a wall flow structure having a porous partition wall 16 that partitions an inlet cell and an outlet cell, and a wash coat layer held on surfaces of internal pores of the partition wall. In addition, average filling rates A, B, and C of the wash coat layer measured for each predetermined pore diameter range in the internal pores satisfy specific relationships. Further, the wash coat layer is formed in a region that occupies 50% or more of a thickness of the partition wall, and an amount of a noble metal catalyst carried by the wash coat layer is 0 g/L or more but 0.2 g/L or less.

An ammonia oxidation catalyst device, including a substrate, a first catalyst coat layer and a second catalyst coat layer, wherein: the first catalyst coat layer includes inorganic oxide particles and a catalytic noble metal supported on the inorganic oxide particles; the second catalyst coat layer includes an NO.sub.x selective reduction catalyst and a proton zeolite H-Zeolite; the first catalyst coat layer is present on the substrate; and the second catalyst coat layer is present on the first catalyst coat layer.

Described is a method of coating the inside of an exhaust gas purification catalyst filter with a predetermined amount of catalyst slurry while adjusting the distribution of catalyst components in or on a cell wall of the filter. A predetermined amount of catalyst slurry can be injected into an internal channel of a filter to solve conventional problems caused by excess or surplus slurry injection. The predetermined amount of slurry injected into the internal channel of the filter is coated on or in the cell wall, depending on the viscosity and particle size of the slurry. This enables a coating profile in which the slurry distribution at a front portion of the filter and the slurry distribution at a back portion of the filter differ from each other. In addition, the coating profile on the inner surface of the cell wall or in the pores of the cell wall can be adjusted through the subsequent air blowing, so that the back pressure of the filter and the performance of the catalyst filter, such as catalytic activity, can be improved. In addition, the coating length in the filter can be adjusted by controlling the pressure of air during the air blowing.

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.

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 present invention provides an exhaust gas purification catalyst having an excellent purification performance for purifying chemically stable methane. A catalyst material 30 includes a carrier 32 formed of alumina and a catalyst 34 formed of at least one of palladium and a palladium oxide directly supported on the carrier 32. A specific surface area of the carrier 32 is preferably 20 m.sup.2/g or more 90 m.sup.2/g or less. In one preferred aspect, a proportion of Pd(100) and PdO(101) in crystal planes of the catalyst 34 at a joint surface between the catalyst 34 and the carrier 32 is 20 number % or more.