An exhaust gas treatment system includes in order: an intake for receiving an exhaust gas from a lean burn combustion engine; an injector for the provision of a nitrogenous reductant; a close-coupled vanadium-containing SCR catalyst composition; one or more downstream PGM-containing oxidation catalyst compositions, wherein the close-coupled vanadium-containing SCR catalyst composition includes cerium in a Ce:V molar ratio of greater than 0.3.

The present invention relates to a catalyst comprising a carrier substrate of the length L extending between substrate ends a and b and two washcoat zones A and B, wherein washcoat zone A comprises a first platinum group metal and extends starting from substrate end a over a part of the length L, and washcoat zone B comprises the same components as washcoat zone A and in addition a second platinum group metal and extends from substrate end b over a part of the length L, wherein L=L.sub.A+L.sub.B, wherein L.sub.A is the length of washcoat zone A and L.sub.B is the length of substrate length B.

Described herein is a layered catalytic article which includes a) a top layer including a front zone and a rear zone, where the front zone includes a palladium component and a rhodium component, supported individually or together on a support, and the rear zone includes a platinum component, a rhodium component and optionally a palladium component, supported individually or together on a support; b) a bottom layer including a platinum component and a palladium component supported individually or together on a support; and c) a substrate. Also described herein are an exhaust treatment system including the layered catalytic article and a method of using the layered catalytic article for abatement of hydrocarbons, carbon monoxide and nitrogen oxides in an exhaust stream.

The present invention relates to a wall flow filter, to a method for the production and the use of the filter for reducing harmful exhaust gases of an internal combustion engine. Particle filters are commonly used for filtering exhaust gases from a combustion process. Also disclosed are novel filter substrates and their specific use in exhaust gas aftertreatment.

A compression ignition internal combustion engine (30) for a heavy-duty diesel vehicle comprising an exhaust system (32) comprising a composite oxidation catalyst (12, 42) and a soot filter substrate (44, 50) disposed downstream from the composite oxidation catalyst comprising: a substrate (5), preferably a honeycomb flow-through substrate monolith, having a total length L and a longitudinal axis and having a substrate surface extending axially between a first substrate end (I) and a second substrate end (O); two catalyst washcoat zones (1, 2) arranged axially in series on and along the substrate surface, wherein a first catalyst washcoat zone (1) having a length L.sub.1 and comprising a first catalyst washcoat layer (9), wherein L.sub.1<L, is defined at one end by the first substrate end (I) and at a second end by a first end (15) of a second catalyst washcoat zone (2) having a length L.sub.2 and comprising a second catalyst washcoat layer (11), wherein L.sub.2<L, wherein the second catalyst washcoat zone (2) is defined at a second end thereof by the second substrate end (O), and wherein the first substrate end (I) of the composite oxidation catalyst (12, 42) is oriented to an upstream side and wherein the first catalyst washcoat zone (1) comprises a first refractory metal oxide support material and two or more platinum group metal components supported thereon comprising both platinum and palladium at a weight ratio of platinum to palladium of <1; and the second catalyst washcoat zone (2) comprises a second refractory metal oxide support material and one or more platinum group metal components supported thereon; and a washcoat overlayer (G) extending axially from the first substrate end (I) comprising a particulate metal oxide having a loading of >48.8 g/l (>0.8 g/in.sup.3), wherein a total platinum group metal loading in the first catalyst washcoat zone (1) defined in grams of platinum group metal per litre of substrate volume (g/l) is greater than a total platinum group metal loading in the second catalyst washcoat zone (2) and wherein the first catalyst washcoat zone (1) comprises one or more first alkaline earth metal components, preferably barium, supported on the first refractory metal oxide support material.

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; a first catalytic region comprising a first platinum group metal (PGM) component and a first PGM support material, wherein the first catalytic region comprises up to 5 wt. % Sn.

Proposed inventions are a recipe of denitrification-oxidation complex catalyst containing an SCR catalyst and an oxidation catalyst to simultaneously remove nitrogen oxides, carbon monoxide, hydrocarbons, and ammonia, a manufacturing method thereof, an exhaust gas treatment method using the denitrification-oxidation complex catalyst, and an SCR denitrification system including the denitrification-oxidation complex catalyst. The denitrification-oxidation complex catalyst simultaneously removes nitrogen oxides, carbon monoxide, hydrocarbons, and ammonia and exhibits an increased catalytic effect compared to the cases where the denitrification catalyst used alone and the denitrification and the oxidation catalyst ratios are and not properly balanced. When the denitrification-oxidation complex catalyst is applied to an SCR denitrification system, the structure is simplified, space is saved, cost is reduced, and catalyst maintenance is easy.

The present disclosure is directed to a system for treating an exhaust gas stream from an engine, which includes a diesel oxidation catalyst (DOC) located downstream of the engine and adapted for oxidation of hydrocarbons and carbon monoxide, an injector adapted for the addition of a reductant to the exhaust gas stream located downstream of the DOC, a catalyzed soot filter (CSF) located downstream of the injector, and a selective catalytic reduction component adapted for the oxidation of nitrogen oxides located downstream of the CSF. The CSF is adapted for oxidizing hydrocarbons and includes a selective oxidation catalyst composition on a filter with high selectivity ratio for hydrocarbon oxidation:ammonia oxidation (e.g., at least 0.6).

An oxidation catalyst for treating an exhaust gas from a compression ignition engine, which oxidation catalyst comprises: a substrate; a first washcoat region comprising palladium (Pd) and a first support material comprising cerium oxide; and a second washcoat region comprising platinum (Pt) and a second support material.

A method of treating exhaust gas from a lean burn internal combustion engine is disclosed. The method comprises: introducing ammonia or an ammonia precursor into the exhaust gas upstream of an Fe-SCR catalyst, the Fe-SCR catalyst comprising iron and a zeolite; and contacting the exhaust gas with the Fe-SCR catalyst; wherein the amount of ammonia or ammonia precursor introduced into the exhaust gas upstream of the Fe-SCR catalyst is controlled to provide an ammonia-to-NO.sub.x molar ratio (ANR) in the exhaust gas contacting the Fe-SCR catalyst of from greater than 2 to 6.