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, an outlet end with an axial length L; an inlet catalyst layer beginning at the inlet end and extending for less than the axial length L, wherein the inlet catalyst layer comprises an inlet palladium component; an outlet catalyst layer beginning at the outlet end and extending for less than the axial length L, wherein the outlet catalyst layer comprises an outlet rhodium component; and wherein the outlet catalyst layer overlaps with the inlet catalyst layer.

An oxidation catalyst is described for treating an exhaust gas from a diesel engine, which oxidation catalyst comprises: a substrate; a first washcoat region disposed on the substrate, wherein the first washcoat region comprises a first platinum group metal (PGM) and a first support material; a second washcoat region adjacent to the first washcoat region, wherein the second washcoat region comprises a second platinum group metal (PGM) and a second support material; a third washcoat region disposed on the substrate, wherein the third washcoat region comprises a third platinum group metal (PGM) and a third support material; and wherein either: (i) the third washcoat region is adjacent to the second washcoat region; or (ii) the second washcoat region is disposed or supported on the third washcoat region. Also described are uses and methods involving the oxidation catalyst.

A composite, zone-coated, dual-use ammonia (AMOX) and nitric oxide oxidation catalyst (12) comprises: a substrate (5) 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 or more catalyst washcoat zones (1; 2) comprised of a first catalyst washcoat layer (9) comprising a refractory metal oxide support material and one or more platinum group metal components supported thereon and a second catalyst washcoat layer (11) different from the first catalyst washcoat layer (9) and comprising a refractory metal oxide support material and one or more platinum group metal components supported thereon, which two or more catalyst washcoat zones (1; 2) being arranged axially in series on and along the substrate surface, wherein a first catalyst washcoat zone (1) having a length L.sub.1, wherein L.sub.1<L, is defined at one end by the first substrate end (I) and at a second end (13) by a first end (15) of a second catalyst washcoat zone (2) having a length L.sub.2, wherein L.sub.2<L, wherein the first catalyst washcoat zone (1) comprises a first refractory metal oxide support material and one or more platinum group metal components supported thereon; and the second catalyst washcoat zone 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 for up to 200% of the axial length of the underlying first catalyst washcoat layer, which washcoat overlayer comprising a particulate metal oxide loading of >48.8 g/l (>0.8 g/in.sup.3), wherein the particulate metal oxide is an aluminosilicate zeolite including at least one of copper, iron and manganese, 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 different from the total platinum group metal loading in the second catalyst washcoat zone (2).

A selective catalytic reduction catalyst for the treatment of an exhaust gas stream of a passive ignition engine, the catalyst comprising a porous wall-flow filter substrate comprising an inlet end, an outlet end, a substrate axial length (w) extending between the inlet end and the outlet end, and a plurality of passages defined by porous internal walls of the porous wall flow filter substrate; wherein the catalyst further comprises a first coating, said first coating extending over x % of the substrate axial length from the inlet end toward the outlet end of the substrate, x being in the range of from 10 to 100, wherein the first coating comprises copper and an 8-membered ring pore zeolitic material; wherein the catalyst further comprises a second coating, the second coating extending over y % of the substrate axial length from the outlet end toward the inlet end of the substrate, y being in the range of from 20 to 90, wherein the second coating comprises copper, and optionally an 8-membered ring pore zeolitic material; wherein the catalyst optionally further comprises a third coating; wherein x+y is at least 90; wherein y % of w from the outlet end toward the inlet end of the substrate define the outlet zone of the coated substrate and (100−y) % of w from the inlet end toward the outlet end of the substrate define the inlet zone of the coated substrate; wherein the ratio of the loading of copper in the inlet zone, Cu(in), calculated as CuO, relative to the loading of copper in the outlet zone, Cu(out), calculated as CuO, Cu(in):Cu(out), is less than 1:1.

A catalyst composition for treating an exhaust gas, the catalyst composition comprising a molecular sieve, the molecular sieve comprising exchanged copper and exchanged manganese.

The present disclosure provides Low Temperature NO.sub.x-Absorber (LT-NA) catalyst compositions, catalyst articles, and an emission treatment system for treating an exhaust gas, each including the LT-NA catalyst compositions. Further provided are methods for reducing a NO.sub.x level in an exhaust gas stream using the LT-NA catalyst articles. In particular, the LT-NA catalyst compositions include a first zeolite, a first palladium component, and a plurality of platinum nanoparticles. The LT-NA catalyst compositions exhibit enhanced regeneration efficiency with respect to NO.sub.x adsorption capacity, even after hydrothermal aging.

There is provided an exhaust gas purification device that shows a high HC removal performance under a condition in which a rich air-fuel mixture is introduced. The exhaust gas purification device includes a substrate, a first catalyst layer, and a second catalyst layer. The substrate includes an upstream end and a downstream end. The first catalyst layer is disposed on a surface of the partition wall in an upstream region including the upstream end of the substrate. The second catalyst layer is disposed inside the partition wall in a downstream region including the downstream end of the substrate. The first catalyst layer contains a first metal catalyst and alumina-zirconia composite oxide. The second catalyst layer contains a second metal catalyst.

The present invention relates to a diesel oxidation catalyst comprising a carrier body having a length L extending between a first end face and a second end face, and differently composed material zones A and B arranged on the carrier body, wherein material zone A comprises platinum and palladium applied to a cerium-titanium mixed oxide, and material zone B comprises platinum and palladium applied to a carrier oxide B.

An automotive catalytic converter includes a three-way catalyst having Rh as the only precious metal configured as a front zone and a three-way catalyst having a mixture of Rh and Pd, Pt, or both configured as a rear zone, such that an exhaust gas from an internal combustion engine passes through the front zone before passing through the rear zone to minimize sulfur poisoning of the catalytic converter.

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 oxygen storage capacity (OSC) material, wherein the first OSC material has a fresh specific surface area (SSA) of at least 10 m.sup.2/g; and wherein the first OSC material has an SSA difference of no more than 30 m.sup.2/g between the fresh first OSC material and the aged first OSC material.