A catalyst article including a substrate with an inlet side and an outlet side, a first zone and a second zone, where the first zone includes a passive NOx adsorber (PNA), and an ammonia slip catalyst (ASC) comprising a platinum group metal on a support and a first SCR catalyst; where the second zone includes a catalyst selected from the group consisting of a diesel oxidation catalyst (DOC) and a diesel exotherm catalyst (DEC); and where the first zone is located upstream of the second zone. The first zone may include a bottom layer with a blend of: (1) the platinum group metal on a support and (2) the first SCR catalyst; and a top layer with a second SCR catalyst, the top layer located over the bottom layer.

A catalyst article and its use in an exhaust system for internal combustion engines is disclosed. The catalyst article comprises a substrate which is a wall-flow filter, a first catalyst composition, and a second catalyst composition. The first and second catalyst compositions each independently comprise an oxygen storage component (OSC) derived from a CeZr mixed oxide sol having a D90 of less than 1.3 micron and a particulate inorganic oxide having a D90 of from 1 to 20 microns.

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.

Provided herein is a catalytic article including a catalytic coating disposed on a substrate, wherein the catalytic coating comprises a bottom coating on the substrate and a top coating layer on the bottom coating layer, one such coating layer containing a platinum group metal on a refractory metal oxide support and the other such coating layer containing a ceria-containing molecular sieve. Such catalytic articles are effective toward treating exhaust gas streams of internal combustion engines and exhibit outstanding resistance to sulfur.

A phosphorus compound-containing exhaust gas purifying catalyst includes: a refractory three-dimensional structure extending from a gas inflow side end surface to a gas outflow side end surface, the refractory three-dimensional structure having cell walls that define and form multiple gas flow paths, the gas flow paths running from the gas inflow side end surface to the gas outflow side end surface; a lower catalyst layer that contains Pd and is formed continuously from the gas inflow side end surface on the cell walls; a gas inflow side upper catalyst layer that contains Rh and is located as an uppermost layer on the cell walls; and a gas outflow side upper catalyst layer that contains Rh and is located as an uppermost layer on the cell walls.

This exhaust gas purification catalyst device includes an upper layer which includes first carrier particles and rhodium, and a lower layer which includes second carrier particles, and the upper layer includes a rhodium enriched area in the range a, from the downstream end in the exhaust gas flow to greater than 50% and up to 80% of the upper layer length, and a range b from the upper layer top surface less than 20 m in the depth direction. The rhodium enriched area contains at least 50% and less than 100% of all the rhodium in the upper layer.

Provided is, for example, an exhaust gas-purifying three-way catalyst which is small in the amount of a platinum group element used, which can be early increased in temperature to a catalytically active temperature, which is suppressed in degradation in performance due to a catalyst poison included in an exhaust gas even if placed directly under an engine, and which is excellent in purification performance. An exhaust gas-purifying three-way catalyst including at least a catalyst carrier 11 and a catalyst layer 21, wherein the catalyst layer 21 has a layered structure having at least a first catalyst layer L1, a second catalyst layer L2 and a third catalyst layer L3 in the listed order, the first catalyst layer L1 contains a first composite catalyst particle including palladium supported on a first base material particle, the second catalyst layer L2 contains a second composite catalyst particle including rhodium supported on a second base material particle, the third catalyst layer L3 contains a third composite catalyst particle including palladium supported on a third base material particle, and the total coating weight Wt in the catalyst layers L1, L2, and L3 (provided that the platinum group element included in each of the catalyst layers is excluded) is 110 g/L or more and 225 g/L or less in total, per volume of the catalyst carrier 11.

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 redox active base metal and palladium supported on a zeolite and/or refractory oxide support and extends starting from substrate end a over a part of the length L, and washcoat zone B comprises the same components as washcoat A and an additional amount of palladium 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.

A catalyst article including a substrate with an inlet end and an outlet end, a first zone and a second zone, where the first zone comprises: a) an ammonia slip catalyst (ASC) bottom layer comprising a platinum group metal on a support; and b) an SCR layer comprising a second SCR catalyst, the SCR layer located over the ASC bottom layer; where the second zone comprises a catalyst (second zone catalyst) selected from the group consisting of a diesel oxidation catalyst (DOC) and a diesel exotherm catalyst (DEC); wherein the ASC bottom layer extends into the second zone; and where the first zone is located upstream of the second zone. The ASC bottom layer may include a blend of: (1) the platinum group metal on a support and (2) a first SCR catalyst.

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.