Provided are: a hydrocarbon adsorbent capable of adsorbing hydrocarbons, storing the adsorbed hydrocarbons up to a relatively high temperature, and desorbing the adsorbed and stored hydrocarbons at a relatively high temperature; an exhaust gas purifying catalyst composition using the same; an exhaust gas purifying catalyst; and a method for treating an exhaust gas. The hydrocarbon adsorbent comprises a zeolite having an MRT-type framework structure. The hydrocarbon adsorbent comprises a small-pore zeolite having a total desorption amount ZD.sub.1 of propylene desorbed at 50° C. or higher and lower than 300° C. being 3.5 mmol/g or less and a total desorption amount ZD.sub.2 of propylene desorbed at 300° C. or higher and 500° C. or lower being 0.5 mmol/g or more, per 1 g by mass of the small-pore zeolite, when adsorbing propylene at 50° C. and then heating from 50° C. to 500° C. under the condition of 10° C./min by a temperature-programmed desorption method.

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 comprising an inlet end, an outlet end with an axial length L; an inlet catalyst layer beginning at the inlet end and extending for less than the axial length L, wherein the inlet catalyst layer comprises an inlet palladium component; an outlet catalyst layer beginning at the outlet end and extending for less than the axial length L, wherein the outlet catalyst layer comprises an outlet rhodium component; and wherein the outlet catalyst layer overlaps with the inlet catalyst layer.

The present application relates to a cerium-tin-based composite oxide catalyst for catalyzing purification of a nitrogen oxide, a preparation method and an application thereof. The catalyst has the following chemical composition: a cerium-tin oxide and an M oxide, wherein the M is selected from any one of or a combination of at least two of P, Ti, Zr, V, Mn, Fe, Cu, Al, Si, Ni, Hf, Nb, Ta, Cr, Mo, W, or Re. According to the present application, a cerium-tin-based composite oxide catalyst having the characteristics such as high catalytic activity, high hydrothermal stability, excellent N.sub.2 generation selectivity, a wide operation temperature window, and adaptation to high space velocity reaction conditions is prepared by means of a non-toxic and harmless raw material and a simple method, and the present application is applicable to a device for catalyzing purification of a mobile source nitrogen oxide represented by diesel vehicle exhaust gas and a fixed source nitrogen oxide represented by flue gas from a coal-fired power plant.

The present invention relates to a catalyst comprising two layers on an inert catalyst carrier, a layer A containing at least palladium as a platinum group metal, in addition to a cerium/zirconium/lanthanum/yttrium mixed oxide, and a layer B, which is applied to layer A, containing at least rhodium as the platinum group metal, in addition to a cerium/zirconium/lanthanum/yttrium mixed oxide.

An exhaust gas treatment device includes a housing having a wall. The wall of the housing defines an interior chamber. A substrate is supported by the housing within the interior chamber of the housing. The substrate extends along a longitudinal axis. The substrate includes a flow through structure that allows the flow of exhaust gas to flow through the substrate. The substrate includes a catalytic composition disposed thereon for reacting with the flow of exhaust gas. The substrate includes a cavity, extending along a cavity axis, which is transverse to the longitudinal axis of the substrate. A sensor is attached to the housing. The sensor includes a probe that at least partially extends into the cavity of the substrate, for sensing a gaseous component in the flow of exhaust gas. The cavity mixes the flow of exhaust gas and directs the exhaust gas toward the probe of the sensor.

A hydrocarbon adsorbent having high hydrocarbon adsorbing properties even after exposed to a high temperature/high humidity reducing atmosphere, includes a FAU type zeolite having in ESR measurement a spin concentration of a least 1.0 × 10^19 (spins/g) and a ratio of a peak intensity at a magnetic field of at least 260 mT and at most 270 mT to a peak intensity at a magnetic field of at least 300 mT and at most 320 mT of at least 0.25 and at most 0.50 Å and containing bivalent copper. The hydrocarbon adsorbent may be used for a method for adsorbing hydrocarbons to be exposed to a high temperature/high humidity environment, and may be used particularly for a method for adsorbing hydrocarbons in an exhaust gas of an internal combustion engine, such as an automobile exhaust gas.

An oxidation catalyst composition is provided, the composition including a plurality of platinum group metal particles having a multi-modal distribution of particle sizes. The plurality of platinum group metal particles includes a first population of platinum group metal particles having a range of particle sizes of from about 0.5 nm to about 3 nm, and a second population of platinum group metal particles having a range of particle sizes of from about 4 nm to about 15 nm. Methods for the preparation and use of the catalyst composition are also provided, as well as catalyst articles and emission gas treatment systems employing such catalyst articles. The catalyst exhibits enhanced stability with respect to oxidation performance after degreening and/or aging, as compared to conventional oxidation catalysts, in particular less loss of NOx oxidation performance.

An object of the present invention is to increase the reduction performance of nitrogen oxides compared to existing three-way catalysts; simultaneously inhibit the emission of ammonia and nitrous oxide; simplify a process by means of a method of further doping an iridium-ruthenium catalyst into a commercial three-way catalyst; and expand the scope of application. The present invention provides a catalyst for simultaneously inhibiting the emission of ammonia and nitrous oxide by doping an iridium-ruthenium catalyst component into a three-way catalyst (TWC), a diesel oxidation catalyst, or a lean NOx trap supported on a honeycomb support.

Provided is a preparation method of a coating material. The method includes: using an aluminum salt and a silicon source as precursors; and performing hydrothermal crystallization and calcination treatments successively under an action of a template agent to obtain the coating material, wherein the template agent is used to cause the coating material to form a porous spherical structure. In the embodiments of the present disclosure, the preparation process of the coating material is simple and the cost is low, and the specific surface area of the prepared coating material is large.

This exhaust gas purifying catalyst is provided with a substrate and a catalyst layer formed on a surface of the substrate. The catalyst layer contains zeolite particles that support a metal, and a rare earth element-containing compound that contains a rare earth element. The rare earth element-containing compound is added in such an amount that the molar ratio of the rare earth element relative to Si contained in the zeolite is 0.001 to 0.014 in terms of oxides.