An exhaust gas purification catalyst for providing removal performance of methane, which is chemically stable includes a substrate that divides cells through which an exhaust gas flows and a catalyst layer that is provided on a surface of the substrate. The catalyst layer includes a palladium layer containing palladium that extends from a first end part which is an end part on the side of the cells into which an exhaust gas flows to a second end part which is an end part on the side from which an exhaust gas flows out, a platinum layer containing platinum that extends from the second end part to the first end part, and a rhodium layer containing rhodium that is laminated on both the palladium layer and the platinum layer.

A composite oxidation catalyst (18, 20) for use in an exhaust system for treating an exhaust gas produced by a vehicular compression ignition internal combustion engine (30) and upstream of a particulate matter filter (44, 50) in the exhaust system 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); and three or more catalyst washcoat zones (1, 2, 3; or 1, 2, 3, 4) 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 by a first end (19, 21) 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 two or more platinum group metal components supported thereon comprising both platinum and palladium at a weight ratio of platinum to palladium of ≥1; 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 third catalyst washcoat zone (3) comprising a third refractory metal oxide support material and one or more platinum group metal components supported thereon is defined at a second end thereof by the second substrate end (O), wherein a total platinum group metal loading in the first catalyst washcoat zone (1) defined in grams of platinum group metal per cubic foot of substrate volume (g/l) (g/ft.sup.3) is greater than a total platinum group metal loading in the second catalyst washcoat zone (2), wherein a total platinum group metal loading in the third catalyst washcoat zone (3) defined in grams of platinum group metal per cubic foot of substrate volume (g/l) (g/ft.sup.3) is less than the 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 supported on the first refractory metal oxide support material.

The invention relates to a selective ammonia oxidation catalysts comprising a platinum group metal and a support comprising TiO2 doped with 0-10% by weight of SiO.sub.2, WO.sub.3, ZrO.sub.2, Y.sub.2O.sub.3, La.sub.2O.sub.3, or a mixture thereof. The invention further comprises methods for the manufacture of the selective ammonia oxidation catalysts, and integrated catalyst systems comprising the selective ammonia oxidation catalysts for treating an exhaust gas stream.

A three-way catalyst having low NH.sub.3 formation is disclosed. The catalyst includes a carrier and a coating material. The coating material includes a precious metal active component and a catalytic material. The precious metal active component includes a first precious metal active component and a second precious metal active component. The first precious metal active component is a composition containing Ru. The second precious metal active component is a composition containing Pt, Pd and Rh. Alternatively, the second precious metal active component is a composition containing Pd and Rh.

Disclosed herein are monolith oxidation catalysts for the destruction of CO and volatile organic compounds (VOC) chemical emissions, in particular, the destruction of light alkane organic compounds. The catalysts contain high surface area refractory oxides of silica- and hafnia-doped zirconia and silica, or tin oxide or stabilized alumina; and at least one platinum group metals, in particular platinum metal, or a combination of platinum and palladium

The present disclosure generally provides catalysts, catalytic articles and catalyst systems including such catalytic articles. In particular, the catalyst composition includes a zeolite having a chabazite (CHA) crystal structure ion-exchanged with iron and copper. Methods of making and using the catalyst composition are also provided, as well as emission treatment systems containing a catalyst article coated with the catalyst composition. The catalyst article present in such emission treatment systems is useful to catalyze the reduction of nitrogen oxides in gas exhaust in the presence of a reductant.

Provided is a composition comprising alumina, the alumina being surface-modified with a perovskite type compound of formula (I); wherein formula (I) is defined by A.sub.x-yA′.sub.yB.sub.1. .sub.zB′.sub.zO.sub.3; where: A is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; A′ is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; B is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir; B′ is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir; x is from 0.7 to 1; y is from 0 to 0.5; and z is from 0 to 0.5.

Provided is a composition comprising a ceria-zirconia mixed oxide, the ceria-zirconia mixed oxide being surface-modified with a perovskite type compound of formula (I); wherein formula (I) is defined by A.sub.x-yA′.sub.yB.sub.1-zB′.sub.zO.sub.3; where: A is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; A′ is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; B is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir; B′ is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir; x is from 0.7 to 1; y is from 0 to 0.5; and z is from 0 to 0.5.

Provided is an exhaust gas purification device that allows improving an exhaust gas purification performance. An exhaust gas purification device of the present disclosure includes a substrate and a catalyst layer disposed on the substrate. The catalyst layer contains a porous carrier, a catalytic metal that is supported by the porous carrier and belongs to platinum group, an alkaline earth metal supported by the porous carrier, and an alkaline earth metal not supported by the porous carrier. At least a part of the alkaline earth metal supported by the porous carrier is supported inside the porous carrier.

This exhaust gas cleaning catalytic device includes a base material and a first catalyst coat layer on the base material. The first catalyst coat layer has a pre-stage section on an exhaust gas flow upstream side, and a post-stage section on an exhaust gas flow downstream side. The first catalyst coat layer pre-stage section and post-stage section each contain inorganic oxide particles and rhodium supported by the inorganic oxide particles, while at least some of the inorganic oxide particles contain ceria. The ceria amount per unit length of the first catalyst coat layer post-stage section is larger than the ceria amount per unit length of the first catalyst coat layer pre-stage section. The first catalyst coat layer pre-stage section is disposed in such a manner that the end portion on the exhaust gas flow upstream side thereof is in direct contact with the exhaust gas flow.