A NO.sub.x adsorber catalyst and its use in an emission treatment system for internal combustion engines, is disclosed. The NO.sub.x adsorber catalyst comprises a first layer consisting essentially of a support material, one or more platinum group metals disposed on the support material, and a NO.sub.x storage material.

An oxidation catalyst for treating an exhaust gas from a diesel engine, which oxidation catalyst comprises: a first washcoat region comprising platinum (Pt), manganese (Mn) and a first support material; a second washcoat region comprising a platinum group metal (PGM) and a second support material; and a substrate having an inlet end and an outlet end; wherein the second washcoat region is arranged to contact the exhaust gas at the outlet end of the substrate and after contact of the exhaust gas with the first washcoat region.

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.

An oxidation catalyst for treating an exhaust gas from a diesel engine comprises: a first washcoat region for oxidising carbon monoxide (CO) and hydrocarbons (HCs), wherein the first washcoat region comprises a first platinum group metal (PGM) and a first support material, and wherein the first washcoat region does not comprise manganese or an oxide thereof; a second washcoat region for oxidising nitric oxide (NO), wherein the second washcoat region comprises platinum (Pt), manganese (Mn) and a second support material comprising a refractory metal oxide, which is silica-alumina or alumina doped with silica in a total amount of 0.5 to 45% by weight of the alumina, wherein the platinum (Pt) is disposed or supported on the second support material and the manganese (Mn) is disposed or supported on the second support material; and a substrate having an inlet end and an outlet end, and wherein the first washcoat region is a first washcoat layer and the second washcoat region is a second washcoat layer, and the second washcoat layer is disposed on the first washcoat layer; and wherein when the oxidation catalyst comprises a hydrocarbon adsorbent, which is a zeolite, then the first washcoat region further comprises the hydrocarbon adsorbent.

A multi-function catalyst article for treating both NO and carbon monoxide emissions in a flow of a combustion exhaust gas from a stationary emission source comprises a honeycomb monolith substrate comprising one or more channels which are open at both ends and extend along an axial length thereof and through which, in use, a combustion exhaust gas flows, which catalyst article comprising a catalyst composition comprising a combination of a first, vanadium-containing SCR catalyst component and a second component which is a compound of a transition metal comprising copper, manganese, cobalt, molybdenum, nickel or cerium or a mixture of any two or more thereof and optionally a third, crystalline molecular sieve component.

Systems, methods, and apparatus are contemplated in which a tube cell that produces a dielectric barrier discharge (DBD) is individually configured to minimize the mixing of unwanted byproducts of the generated plasma with an exhaust air stream. The tube cell generates a DBD within a tube cell, such that oxidants or radicals are generated in an environment substantially separated from the exhaust stream. The generated oxidants are directed to intersect with the exhaust stream to minimize the generation of unwanted byproducts. The tube cells are further shaped and arranged in tube cell arrays to alter the flow dynamics of the exhaust stream and the oxidant or radical streams, including mixing of the streams.

Provided is a porous structure for exhaust purification catalysts having excellent light-off temperature characteristics. The porous structure for exhaust purification catalysts includes an oxygen storage component and an inorganic porous solid. The porous structure has a pore volume distribution such that the ratio of the pore volume of pores with a diameter of from 15 nm to less than 25 nm to the pore volume of pores with a diameter of from 5 nm to less than 15 nm is 1.3 to 2.5 as measured with a mercury porosimeter. The pore volume distribution preferably has at least one peak top in a pore diameter range of from 15 nm to less than 25 nm.

Systems, methods, and apparatus are contemplated in which a tube cell that produces a dielectric barrier discharge (DBD) is individually configured to minimize the mixing of unwanted byproducts of the generated plasma with an exhaust air stream. The tube cell generates a DBD within a tube cell, such that oxidants or radicals are generated in an environment substantially separated from the exhaust stream. The generated oxidants are directed to intersect with the exhaust stream to minimize the generation of unwanted byproducts. The tube cells are further shaped and arranged in tube cell arrays to alter the flow dynamics of the exhaust stream and the oxidant or radical streams, including mixing of the streams.

The present disclosure generally provides catalysts, catalyst articles and catalyst systems including such catalyst articles. In particular, the catalyst composition includes a metal ion-exchanged molecular sieve ion-exchanged with at least one additional metal, which reduces the number of metal centers often present in metal promoted zeolite catalysts. Methods of making and using the catalyst composition are also provided, as well as emission treatment systems including a catalyst article coated with the catalyst composition. The catalyst article present in such emission treatment systems is useful to catalyze the reduction of nitrogen oxides in gas exhaust in the presence of a reductant while minimizing the amount of dinitrogen oxide emission.

Provided is a porous structure for exhaust purification catalysts having excellent light-off temperature characteristics. The porous structure for exhaust purification catalysts includes an oxygen storage component and an inorganic porous solid. The porous structure has a pore volume distribution such that the ratio of the pore volume of pores with a diameter of from 15 nm to less than 25 nm to the pore volume of pores with a diameter of from 5 nm to less than 15 nm is 1.3 to 2.5 as measured with a mercury porosimeter. The pore volume distribution preferably has at least one peak top in a pore diameter range of from 15 nm to less than 25 nm.