An exhaust gas purification catalyst having an excellent exhaust gas purification ability while reducing the increase in pressure loss. Exhaust gas purification catalyst includes entrance cell, exit cell, and a wall-flow substrate having partition wall to separate these cell, a catalytic layer formed from exhaust inlet-side ends in the extending direction in sections of the interior of partition wall facing entrance cell, and a catalytic layer formed on the surface of partition wall facing exit cell from exhaust outlet-side ends in the extending direction of partition wall, having a length shorter than the entire partition wall length.

Provided is an exhaust gas purification catalyst in which the performance of a catalyst metal can be brought out properly, the purification catalyst boasting excellent purification performance during warm-up of an internal combustion engine. The exhaust gas purification catalyst 10 is provided with a substrate 1 and a catalyst layer. A leading end section 1a positioned upstream in the direction of exhaust gas flow (arrow) has a portion in which the flow rate of exhaust gas is relatively high and a portion in which the flow rate of exhaust gas is relatively low during warm-up of the internal combustion engine. The catalyst, layer in the portion of relatively high flow rate of exhaust gas has a high density section 6 in which a noble metal, is supported at relatively high density. The high density section 6 is formed to be shorter than the total length of the exhaust gas purification catalyst 10 from the leading end section 1a in the direction of exhaust gas flow.

An exhaust gas purification device of the present invention is provided with: a substrate of wall flow structure having an inlet cell, an outlet cell and a porous partition wall; an upstream catalyst layer, provided inside the partition wall and disposed in an upstream portion of the substrate including an exhaust gas inflow end section; and a downstream catalyst layer, provided inside the partition wall and disposed in a downstream portion of the substrate including an exhaust gas outflow end section. The upstream catalyst layer and the downstream catalyst layer each contain a carrier and at least one noble metal from among Pt, Pd and Rh, supported on the carrier. The noble metal in the upstream catalyst layer and the noble metal in the downstream catalyst layer are different from each other.

A catalytic converter with excellent OSC performance and No.sub.x purification performance. The catalytic converter includes a substrate with a cell structure and a catalyst layer formed on a cell wall surface of the substrate. The catalyst layer has a catalyst layer arranged on the upstream side and a catalyst layer arranged on the downstream side in an exhaust gas flow direction on the substrate. The catalyst layer on the upstream side includes a support containing an Al.sub.2O.sub.3—CeO.sub.2—ZrO.sub.2 ternary composite oxide (ACZ material) and an Al.sub.2O.sub.3—ZrO.sub.2 binary composite oxide (AZ material), and at least Rh that is a noble metal catalyst carried on the support, and the catalyst layer on the downstream side includes a support and Pd or Pt that is a noble metal catalyst carried on the support. In the support in the catalyst layer on the upstream side, the mass proportion of ACZ material/(ACZ material+AZ material) is in the range of 0.33 to 0.5, and greater than or equal to 75% mass Rh is carried on the Al.sub.2O.sub.3—ZrO.sub.2 binary composite oxide of the support.

An exhaust gas-purifying catalyst of the present invention comprises a substrate, and one or more catalytic layers provided on the substrate, wherein at least one of the catalytic layers (i) contains a precious metal, alumina, and an acidic oxide element, (ii) has a correlation coefficient ρ.sub.Al,AE of 0.70 or more, and (iii) has a correlation coefficient ρ.sub.PM,AE of 0.70 or more.

A catalyst article having an extruded support having a plurality of channels through which exhaust gas flows during operation of an engine, and a single layer coating or a bi-layer coating on the support, where the extruded support contains a third SCR catalyst, the single layer coating and the bilayer-coating contain platinum on a support with low ammonia storage and a first SCR catalyst. The catalytic articles are useful for selective catalytic reduction (SCR) of NOx in exhaust gases and in reducing the amount of ammonia slip. Methods for producing such articles are described. Methods of using the catalytic articles in an SCR process, where the amount of ammonia slip is reduced, are also described.

Catalyst compositions, articles, systems and methods related to a three-way-catalyst composition comprising alumina doped with a transition metal.

A catalyst converter includes: a substrate (1) having a cell structure formed of a center area (1A) having the highest cell density, a peripheral area (1C) having the lowest cell density, and an intermediate area (1B) having the cell density between that of the center area and that of the peripheral area; a first catalyst layer formed in the center area (1A); a second catalyst layer formed in the intermediate area (1B); and a third catalyst layer formed in the peripheral area (1C). A length in a longitudinal direction of the second catalyst layer is longer than that of the first catalyst layer. A length in the longitudinal direction of the third catalyst layer is longer than that of the second catalyst layer. A ratio of the length in the longitudinal direction of the first catalyst layer to the length of the substrate is 65% or more.

Disclosed is a hydrocarbon gas reforming supported catalyst, and methods for its use, that includes a catalytic material capable of catalyzing the production of a gaseous mixture comprising hydrogen (H.sub.2) and carbon monoxide (CO) from a hydrocarbon gas and a clay support material comprising a clay mineral, wherein the catalytic material is chemically bonded to the clay support material, and wherein the chemical bond is a M1-M2 bond, where M1 is a metal from the catalytic material and M2 is a metal from the clay support material, or the chemical bond is a M1-O bond, where M1 is a metal from the catalytic material and oxygen (O) is from the clay support material, wherein the supported catalyst comprises at least 70% or more by weight of the clay support material.

A selective catalytic reduction (SCR) catalyst includes a support layer. A copper-loaded chabazite (Cu/CHA) layer is supported on the support layer. A copper-loaded beta zeolite (Cu/beta) is supported on the Cu/CHA layer. The Cu/beta may be hydrothermally pre-aged prior to use of the SCR catalyst in a vehicle. The pre-aged Cu/beta is essentially free of phosphorous (P), calcium (Ca), zinc (Zn), sodium (Na), potassium (K), magnesium (Mg), iron (Fe), CaSO.sub.4, Ca.sub.19Zn.sub.2(PO.sub.4).sub.14, CaZn.sub.2(PO.sub.4).sub.2, ash, and/or soot.