The present invention relates to a catalyst comprising a carrier substrate of the length L, which extends between a first end face ‘a’ and a second end face ‘b’, and differently composed material zones A and B arranged on the carrier substrate, wherein material zone A comprises platinum and no palladium or platinum and palladium with a weight ratio of Pt:Pd of ≥1 and, material zone B comprises a copper containing zeolite having a Cu/Al ratio of 0.355 or higher.

Methods for exhaust gas purification, including the steps of: attaching an exhaust gas purification catalyst to an exhaust system of an internal combustion engine, and supplying an exhaust gas to the exhaust gas purification catalyst, where the exhaust gas purification catalyst includes an upper layer containing first carrier particles which are particles of an inorganic oxide and rhodium, and a lower layer containing second carrier particles which are particles of an inorganic oxide, the upper layer includes a rhodium-rich portion near the surface of the upper layer on the upstream side of the exhaust gas flow, and the existence range of the rhodium-rich portion is in a range of greater than 50% to 80% of the length of the upper layer from a downstream side end of an exhaust gas flow and of less than 20 μm in the depth direction from an outermost surface of the upper layer.

An exhaust gas control system according to the present disclosure includes: a first exhaust gas control catalyst layer that controls an exhaust gas emitted from an internal combustion engine; and a second exhaust gas control catalyst layer that further controls the exhaust gas that has been controlled by the first exhaust gas control catalyst layer. The second exhaust gas control catalyst layer contains an oxygen storage material. The ratio of the amount (mmol—CO.sub.2/m.sup.2) of base points per specific surface area (m.sup.2/g) of the oxygen storage material to the specific surface area is equal to or less than 4.50×10.sup.−5.

In accordance with the technology herein disclosed, an exhaust gas purification catalyst exhibiting a high exhaust gas purifying performance using a new rare earth-containing material is provided. The exhaust gas purification catalyst herein disclosed includes a base material and a catalyst layer formed on the surface of the base material. The catalyst layer of such an exhaust gas purification catalyst includes rare earth-carrying alumina 50 including a primary particle of a rare earth particle 40 including at least one rare earth element carried on the surface of an alumina carrier 30 including alumina, and the average particle diameter D.sub.50 based on TEM observation of the rare earth particle 40 in the rare earth-carrying alumina 50 is 10 nm or less. As a result of this, it is possible to provide an exhaust gas purification catalyst having high NOx adsorption performance and CO adsorption performance

An exhaust gas purification catalyst device including a substrate and an SCR catalyst layer on the substrate, the substrate containing catalyst precious metal particles directly supported on the substrate, the catalyst precious metal particles containing Pt, and the catalyst precious metal particles having an average particle diameter of 30 to 120 nm inclusive.

A catalyst composition comprising a first platinum group metal (PGM) component and a first support material, wherein the first PGM component comprises platinum (Pt) and palladium (Pd) and is supported on the first support material; and wherein the first PGM component has a Pt:Pd molar ratio of from about 5:95 to about 95:5.

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 and an outlet end with an axial length L; and a first catalytic region on the substrate; wherein the first catalytic region comprises a first PGM component and a first alumina, wherein the first alumina is doped with a first dopant of at least 5 wt. %, and wherein the first dopant is selected from the group consisting of Zr, Ta, Mo, W, Ti, Nb, and a combination thereof.

Disclosed in the present invention is a tail gas treatment catalyst. The catalyst consists of a carrier, a first catalyst, and a second catalyst. The first catalyst and the second catalyst are provided on both ends of the carrier. The first catalyst can purify pollutants in tail gas. The second catalyst can purify a byproduct, ammonia, obtained by the purification by the first catalyst and pollutants that are not completely purified by the first catalyst. The second catalyst is of a double-layer structure; the lower layer consists of an oxygen storage material, aluminum oxide, and a second active component; the second active component is a composition of Pt and Pd, or a composition of Ce, Fe, Ni and Cu; the upper layer consists of a molecular sieve and a third active component; the third active component is Cu or a composition of Cu and Fe. The tail gas treatment catalyst of the present invention has high purification treatment efficiency, and can significantly reduce the emissions of CH.sub.4, CO, and NO.sub.x in the tail gas, especially reduce the content of the byproduct, NH.sub.3, so that the tail gas can meet China VI emission standards.

Methods for exhaust gas purification, including the steps of: attaching an exhaust gas purification catalyst to an exhaust system of an internal combustion engine, and supplying an exhaust gas to the exhaust gas purification catalyst, where the exhaust gas purification catalyst includes an upper layer containing first carrier particles which are particles of an inorganic oxide and rhodium, and a lower layer containing second carrier particles which are particles of an inorganic oxide, the upper layer includes a rhodium-rich portion near the surface of the upper layer on the upstream side of the exhaust gas flow, and the existence range of the rhodium-rich portion is in a range of greater than 50% to 80% of the length of the upper layer from a downstream side end of an exhaust gas flow and of less than 20 μm in the depth direction from an outermost surface of the upper layer.

An exhaust gas control apparatus includes a honeycomb substrate and an inlet cell-side catalyst layer. The honeycomb substrate includes a porous partition wall that defines a plurality of cells extending from an inlet-side end face to an outlet-side end face. The cells include an inlet cell and an outlet cell that are adjacent to each other with the partition wall therebetween. The inlet cell is open at its inlet-side end and is sealed at its outlet-side end. The outlet cell is sealed at its inlet-side end and is open at its outlet-side end. The inlet cell-side catalyst layer is provided on a surface on the inlet cell side of the partition wall and extends from an inlet-side end of the partition wall. Porosity of the inlet cell-side catalyst layer is in a specific range.