In an exhaust system for a motor vehicle having an exhaust treatment device for after-treating exhaust gas of a combustion engine of the motor vehicle, the exhaust gas treatment device includes a first SCR catalyst, which has a zeolite material containing copper, an ammonia slip catalyst, which is arranged downstream of the first SCR catalyst, and a particulate filter. A second SCR catalyst, which has an SCR catalyst material containing vanadium, is arranged upstream of the first SCR catalyst.

Articles comprising a catalyst film comprising VOx, MoO.sub.3 or WO.sub.3, and TiO.sub.2 deposited on a substrate are disclosed. The articles are useful for selective catalytic reduction (SCR) of NOx in exhaust gases. Methods for producing such articles deposit a catalyst film on the substrate to form a coated substrate, which is then calcined. When used in an SCR process, the coated articles have enhanced activity for NOx conversion, reduced activity for SOx conversion, or both. Light-weight, coated articles having high catalyst loads can be fabricated at the same or reduced dimensions when compared with laminated articles, and increased kNOx/kSOx ratios are available even from coated articles having relatively thin catalyst films. The articles should have particular value for power plant operations, where coal and high-sulfur fuels are commonly used and controlling sulfur trioxide generation is critical.

Porous metal oxide catalytic materials with planar morphologies which are derived from metal-organic framework (MOF) materials via thermal decomposition, oxidation pretreatment and pyrolysis processes. The porous metal oxides are mainly transition metal oxides, derived from MOFs containing the corresponding transition metal ions, such as Cu, Zn, Y, La, Ce, Ti, Zr, V, Cr, Mn, Fe, Co, and Ni ions. The transformation conditions from MOF materials to metal oxides, such as temperature, atmosphere and duration, are well defined to obtain metal oxides with controlled morphologies. Furthermore, the present subject matter relates to a low-temperature catalytic decomposition of volatile organic compounds (VOCs) with a wide concentration range on two-dimensional metal oxides.

The invention relates to a catalyst device for purifying exhaust gases containing nitrogen oxide by using selective catalytic reduction (SCR), the catalyst device comprising at least two catalytic layers, the first layer containing vanadium oxide and a mixed oxide comprising titanium oxide and silicon oxide and the second layer containing a molecular sieve containing iron, wherein the first layer is applied onto the second layer. The invention also relates to uses of the catalyst device and a method for purifying exhaust gases.

Catalyst articles having a first zone containing a first SCR catalyst and a second zone containing an ammonia slip catalyst (ASC), where the ammonia slip catalyst contains a second SCR catalyst and an oxidation catalyst, and the ASC has DOC functionality, where the first zone is located on the inlet side of the substrate and the second zone is located in the outlet side of the substrate are disclosed. The catalytic articles are useful for selective catalytic reduction (SCR) of NOx in exhaust gases, in reducing the amount of ammonia slip and in oxidizing organic residues. Exhaust systems containing the catalyst articles and methods of using the catalytic articles in an SCR process, where the amount of ammonia slip is reduced and hydrocarbon are oxidized by the ASC catalyst, are also described.

The invention provides an exhaust gas treatment system (8) arranged to receive exhaust gases from an internal combustion engine (6), the system comprising an exhaust conduit (10) and a selective catalytic reduction (SCR) catalyst (12) provided in the exhaust conduit (10), characterized in that the system comprises a nitrogen dioxide reducing unit (701) provided in the exhaust conduit (10) upstream of the SCR catalyst (12), wherein the nitrogen dioxide reducing unit (701) is adapted to reduce, at a low temperature, nitrogen dioxide (NO2) in exhaust gases received by the nitrogen dioxide reducing unit (701).

The present invention relates to a diesel oxidation catalyst comprising a substrate and a wash-coat comprising a first layer and a second layer, wherein the substrate has a substrate length, a front end and a rear end, the washcoat comprising the first layer comprising a first metal oxide and comprising a platinum group metal supported on a metal oxide support material; the second layer comprising a second metal oxide and comprising one or more of an oxidic compound of vanadium, an oxidic compound of tungsten and a zeolitic material comprising one or more of Fe and Cu; wherein the first layer is at least partially disposed directly on the substrate, or is at least partially disposed directly on an intermediate layer which is disposed directly on the substrate over the entire length of the substrate, on x % of the length of the substrate from the front end of the substrate, and wherein the second layer is at least partially disposed directly on the substrate, or is at least partially disposed directly on the intermediate layer which is disposed directly on the substrate over the entire length of the substrate, on y % of the length of the substrate from the rear end of the substrate, wherein x is in the range of from 25 to 75 and y is in the range of from 25 to 75 and wherein x+y is in the range of from 95 to 105, wherein the intermediate layer comprises alumina.

System for the removal of noxious compounds and particulate matter from exhaust gas of a compression ignition engine comprising a three way catalyst unit having an NH.sub.3-SCR activity, an ammonia oxidation activity and an adsorption activity of volatile vanadium and tungsten compounds volatilized off an upstream SCR active catalyst.

Presented is a process for the regeneration of a deactivated nitrogen oxide decomposition catalyst used for the selective catalytic reduction of nitrogen oxides contained in a flue gas stream.

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.