The present invention relates to an SCR-active material, comprising a small-pore zeolite, aluminum oxide and copper, characterized in that it contains 5 to 25 wt-% of aluminum oxide in relation to the entire material and that the copper is present on the aluminum oxide in a first concentration and on the small-pore zeolite in a second concentration.

The present invention relates to an SCR-active material, comprising a small-pore zeolite, aluminum oxide and copper, characterized in that it contains 5 to 25 wt-% of aluminum oxide in relation to the entire material and that the copper is present on the aluminum oxide in a first concentration and on the small-pore zeolite in a second concentration.

The invention relates to the use of a catalyst as a passive nitrogen oxide adsorber, which has a carrier substrate, a zeolite, palladium, and platinum, wherein the palladium is provided in a quantity of 0.01 to 10 wt. %, based on the sum of the weights of zeolite, platinum, and palladium and calculated as a palladium metal, and platinum in a quantity of 0.1 to 10 wt. %, based on the weight of the palladium and calculated as a platinum metal. The invention also relates to the use of said catalyst in connection with a SCR catalyst in an exhaust gas system.

The present disclosure generally provides a catalyst composition comprising a zeolite containing iron and/or copper with a reduced amount of extra-framework aluminum. The catalyst composition is useful to catalyze the reduction of nitrogen oxides in exhaust gas in the presence of a reductant.

The present disclosure recognizes a correlation between zeolitic surface area (ZSA) of a catalyst composition and its catalytic activity. Particularly, the disclosure provides catalyst articles for diesel NO.sub.x abatement, including a substrate and a washcoat layer containing metal-promoted molecular sieves, wherein the zeolitic surface area (ZSA) of the catalyst article is about 100 m.sup.2/g or greater, the volumetric surface area is about 900 m.sup.2/in.sup.3 or greater, and/or the total zeolitic surface area (tZSA) is about 1200 m.sup.2 or greater. The disclosure further relates to methods for evaluating ZSA, volumetric ZSA, and tZSA, e.g., including the steps of coating a catalyst composition comprising metal-promoted molecular sieves onto a substrate; calcining and aging the catalyst composition; determining the ZSA (or volumetric ZSA or tZSA) thereof; and correlating the ZSA (or volumetric ZSA or tZSA) with catalyst composition NO.sub.x abatement activity to determine whether the catalyst composition is suitable for an intended use.

A catalyst for oxidising ammonia comprises a selective catalytic reduction (SCR) catalyst and a composite heterogeneous extruded honeycomb having longitudinally extending parallel channels, which channels being defined in part by channel walls having a total longitudinal length, wherein the channel walls comprise a pore structure including a periodic arrangement of porous cells embedded in an inorganic matrix component, at least some of which porous cells are defined at least in part by an active interface layer of a catalytically active material comprising a precious metal supported on particles of a support material.

A catalyst for oxidising ammonia comprises a selective catalytic reduction (SCR) catalyst and a composite heterogeneous extruded honeycomb having longitudinally extending parallel channels, which channels being defined in part by channel walls having a total longitudinal length, wherein the channel walls comprise a pore structure including a periodic arrangement of porous cells embedded in an inorganic matrix component, at least some of which porous cells are defined at least in part by an active interface layer of a catalytically active material comprising a precious metal supported on particles of a support material.

A method of reducing nitrogen oxides in exhaust gas of an internal combustion engine by selective catalytic reduction (SCR) comprises contacting the exhaust gas also containing ammonia and oxygen with a catalytic converter comprising a catalyst (2) comprising at least one crystalline small-pore molecular sieve catalytically active component (Z.sub.M,I) having a maximum ring opening of eight tetrahedral basic building blocks, which crystalline small-pore molecular sieve catalytically active component (Z.sub.M,I) comprising mesopores.

The present invention relates to a process for the manufacture of a copper containing small-pore zeolite which comprisespreparing a reaction mixture comprising a zeolite of the faujasite framework type, Cu-tetraethylenepentamine (Cu-TEPA) and at least one compound M(OH)x, which does not comprise the tetraethylammonium cation andheating the reaction mixture to form a copper containing small-pore zeolite.

The present invention relates to a process for the manufacture of a copper containing small-pore zeolite which comprisespreparing a reaction mixture comprising a zeolite of the faujasite framework type, Cu-tetraethylenepentamine (Cu-TEPA) and at least one compound M(OH)x, which does not comprise the tetraethylammonium cation andheating the reaction mixture to form a copper containing small-pore zeolite.