This exhaust gas cleaning catalytic device includes a base material and a first catalyst coat layer on the base material. The first catalyst coat layer has a pre-stage section on an exhaust gas flow upstream side, and a post-stage section on an exhaust gas flow downstream side. The first catalyst coat layer pre-stage section and post-stage section each contain inorganic oxide particles and rhodium supported by the inorganic oxide particles, while at least some of the inorganic oxide particles contain ceria. The ceria amount per unit length of the first catalyst coat layer post-stage section is larger than the ceria amount per unit length of the first catalyst coat layer pre-stage section. The first catalyst coat layer pre-stage section is disposed in such a manner that the end portion on the exhaust gas flow upstream side thereof is in direct contact with the exhaust gas flow.

The present disclosure provides a selective catalytic reduction (SCR) catalyst composition prepared from a first un-promoted zeolite having a first silica-to-alumina ratio (SAR) from about 5 to about 100, a promoter precursor, and a second un-promoted zeolite having a second silica-to-alumina ratio (SAR) from about 5 to about 100. The present disclosure further provides a method of forming the SCR catalyst composition, a catalytic article comprising the SCR catalyst composition, an engine exhaust gas treatment system comprising the SCR catalyst composition, and a method of removing nitrogen oxides from exhaust gas from a lean burn engine using the SCR catalyst composition.

Catalyzed particulate filters comprise three-way conversion (TWC) catalytic material, which comprises rhodium as the only platinum group metal, that permeates walls of a particulate filter. Such catalyzed particulate filters may be located downstream of close-coupled three-way conversion (TWC) composites in an emission treatment system downstream of a gasoline direct injection engine for treatment of an exhaust stream comprising hydrocarbons, carbon monoxide, nitrogen oxides, and particulates.

The present invention provides a catalytic article comprising a) a first layer comprising a nickel component and a copper component supported on a ceria component, wherein the amount of the nickel component is 0.1 to 30 wt. %, calculated as nickel oxide, based on the total weight of the first layer, and wherein the amount of the copper component is 0.01 to 5.0 wt. % calculated as copper oxide, based on the total weight of the first layer; b) a second layer comprising a platinum group metal component supported on at least one of an oxygen storage component, an alumina component and a zirconia component, wherein the platinum group metal component comprises platinum, rhodium, palladium, or any combination thereof, and wherein the amount of the platinum group metal component is 0.01 to 5.0 wt. % based on the total weight of the second layer; and c) a substrate, wherein the first layer and the second layer are separated by a barrier layer or a gap.

Described are a catalyst capable of effectively oxidizing an exhaust gas, a method for preparing the catalyst, and a method for oxidizing an exhaust gas using the catalyst. The exhaust gas oxidation catalyst includes at least two layers, a lower catalyst layer and an upper catalyst layer, laminated on a three-dimensional structure, wherein the lower catalyst layer and the upper catalyst layer independently contain precious metal and alumina and/or zeolite, and at least a part of the upper catalyst layer contains pores derived from a pore connecting agent with a combustion decomposition temperature of 300° C. or more to less than 450° C.

An exhaust gas purification including: a base of wall flow structure having inlet side cells wherein an end on the exhaust gas inflow side is open and outlet side cells wherein an end on the exhaust gas outflow side is open, and a porous partition wall that partitions the side cells; and first and second catalyst layers disposed in the interior of the porous partition wall so as to be in contact with the side cells, wherein either of the catalyst layers contains an oxidation catalyst but does not contain a reduction catalyst, and the other contains the reduction catalyst but does not contain the oxidation catalyst; and a ratio of the lengths of the catalyst layers differs between a surface of the porous partition wall on the side in contact with the inlet side cells and a surface on the side in contact with the outlet side cells.

An exhaust gas treatment system for an internal combustion engine includes an exhaust gas pathway configured to receive exhaust gas from the internal combustion engine, a first injector configured to selectively introduce a first reductant into the exhaust gas pathway in response to a sensed temperature of the exhaust gas being within a predetermined temperature range, and a first treatment element positioned within the exhaust gas pathway downstream of the first injector. The first treatment element includes a selective catalytic reduction (SCR) layer, a porous filter substrate, and a precious metal catalyst layer. The system also includes a second injector configured to introduce a second reductant into the exhaust gas pathway downstream of the first treatment element and a second treatment element positioned within the exhaust gas pathway downstream of the second injector. The second treatment element includes a SCR element.

The present invention relates to a selective catalytic reduction catalyst for the treatment of an exhaust gas of a diesel engine comprising (i) a flow-through substrate comprising an inlet end, an outlet end, a substrate axial length extending from the inlet end to the outlet end and a plurality of passages defined by internal walls of the flow-through substrate extending therethrough; (II) a coating disposed on the surface of the internal walls of the substrate, where-in the surface defines the interface between the passages and the internal walls, wherein the coating comprises a vanadium oxide supported on an oxidic material comprising titania, and further comprises a mixed oxide of vanadium and one or more of iron, erbium, bismuth, cerium, europium, gadolinium, holmium, lanthanum, lutetium, neodymium, praseodymium, promethium, samarium, scandium, terbium, thulium, ytterbium, yttrium, molybdenum, tungsten, manganese, cobalt, nickel, copper, aluminum and antimony.

The invention relates to a particulate filter for removing particles, carbon monoxide, hydrocarbons and nitrogen oxides out of the exhaust gas of combustion engines operated with stoichiometric air/fuel mixture, comprising a wall flow filter with length L and a coating Z, wherein the wall flow filter includes channels E and A which extend in parallel between a first and a second end of the wall flow filter and are separated by porous walls, which form surfaces OE or OA, and wherein the channels E are closed at the second end and the channels A are closed at the first end, characterised in that coating Z is located in the porous walls and extends from the first end of the wall flow filter over the entire length L, and includes active aluminum oxide, two different cerium/zirconium/rare earth metal mixed oxides and at least one platinum group metal.

A lean NO.sub.x trap catalyst and its use in an emission treatment system for internal combustion engines is disclosed. The lean NO.sub.x trap catalyst comprises a first layer for storing nitrogen oxides (NOx) under lean exhaust gas conditions and releasing and/or reducing stored NOx during rich exhaust gas conditions, and a second layer, said second layer comprising a first zone for oxidizing carbon monoxide (CO) and/or hydrocarbons (HC), and a second zone for oxidizing nitric oxide (NO), and a substrate having an inlet end and an outlet end.