A catalytic converter is provided with: an inlet-side diffuser part; an outlet-side diffuser part; a case including an upstream-side cylindrical part and a downstream-side cylindrical part; an inner liner provided in the upstream-side cylindrical part; a first catalyst retained inside the inner liner; and a second catalyst retained inside the downstream-side cylindrical part. An end face of the second catalyst faces a peripheral surface of the inner liner. An annular flow path is provided between the upstream-side cylindrical part and the inner liner, and the first catalyst is insulated from heat by the annular flow path. A part of exhaust flows into the second catalyst via the annular flow path.

The present invention provides an oxidation catalyst composition suitable for at least partial conversion of gaseous hydrocarbon emissions, e.g., methane. The oxidation catalyst composition includes at least one platinum group metal (PGM) component supported onto a porous zirconia-containing material that provides an effect on hydrocarbon conversion activity. The porous zirconia-containing material is at least 90% by weight in the monoclinic phase. Furthermore, the PGM component can comprise at least one platinum group metal in the form of colloidally deposited nanoparticles. The oxidation catalyst composition can be used in the treatment of emissions from lean compressed natural gas engines.

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.

The presently invention provides an emission control catalyst article comprising a substrate, a bottom washcoat layer comprising a platinum group metal coated on the 60 to 100% length of the substrate, and a top washcoat layer comprising a platinum group metal coated on the 60 to 100% length of the substrate such that the top coat covers at least 60% of the length of the bottom washcoat layer, wherein at least a portion of the top washcoat layer, the bottom washcoat layer or both washcoat layers comprises a platinum group metal deposited within the said washcoat layer(s) with a platinum group metal gradient such that the PGM concentration in a top-most portion of the said washcoat layer is at least two time higher compared to the PGM concentration in a bottom-most portion of the said washcoat layer.

A method of manufacturing a catalyst article, the method comprising: providing a slurry comprising a support material, palladium ions, alkaline-earth-metal ions and an organic compound, wherein the organic compound comprises a functional group selected from a sulfo group (—SO.sub.3H), a sulfonyl group (—S(═O).sub.2—) and a sulfinyl group (—S(═O)—); disposing the slurry on a substrate; and heating the slurry to form nanoparticles of the palladium and nanoparticles of a sulfate of the alkaline earth metal on the support material.

A three-way catalyst article with improved ammonia emission control, and its use in an exhaust system for gasoline engines, is disclosed. The catalyst article for treating exhaust gas from a gasoline engine comprising: a substrate comprising an inlet end, an outlet end with an axial length L; a first catalytic region beginning at the inlet end, wherein the first catalytic region comprises a first zeolite; and a second catalytic region beginning at the outlet end, wherein the second catalytic region comprises a second platinum group metal (PGM) component, a second oxygen storage capacity (OSC) material, and a second inorganic oxide; wherein the second PGM component is selected from the group consisting of palladium, platinum, rhodium and a combination thereof.

The present invention relates to a three-way catalyst (TWC) for treatment of exhaust gases from internal combustion engines operated with a predominantly stoichiometric air/fuel ratio, so called spark ignited engines.

A three-way catalyst article, and its use in an exhaust system for internal combustion engines, is disclosed. The catalyst article for treating exhaust gas comprising: a substrate; and a first catalytic region on the substrate; wherein the first catalytic region comprises a first platinum group metal (PGM) component, wherein the first PGM component comprises PGM nanoparticles, wherein the PGM nanoparticles have an average particle size of about 1 to about 20 nm with a standard deviation (SD) no more than 1 nm.

The present disclosure provides an exhaust gas purification material and an exhaust gas purification device that can efficiently remove harmful components even after being exposed to high temperature. Such exhaust gas purification material comprises metal oxide particles and noble metal particles supported on the metal oxide particles. The noble metal particles have a particle size distribution with a mean of 1.5 nm and 18 nm and a standard deviation of less than 1.6 nm.

The present invention relates to a catalyst comprising two layers on an inert catalyst carrier, wherein a layer A lying directly on the catalyst carrier contains at least one platinum group metal and one cerium/zirconium/SE mixed oxide, and a layer B, applied on layer A and in direct contact with the flow of exhaust gas, contains at least one platinum group metal and a cerium/zirconium/SE mixed oxide, wherein SE stands for a rare earth metal other than from cerium, characterized in that the fraction of SE oxide in the cerium/zirconium/SE mixed oxide of layer A is less than the fraction of SE oxide in the cerium/zirconium/SE mixed oxide of layer B.