Cataler Corporation

Denso Corporation

Yuji Yabuzaki

Kenichi Taki

Akimasa Hirai

Satoshi Matsueda

Sho Hoshino

Keiichi Narita

Tomoaki Nakano

Shingo Nakata

Mitsuyoshi Okada

Masakazu Murata

Daisuke Ochiai

Chihiro Kasuya

Masaaki Kawai

Tomohito Mizukami

Yoshiyasu Andoh

An exhaust gas purification catalyst device has catalyst coating layers, which extend from the upstream side to the downstream side of the exhaust gas flow. The catalyst coating layers each have at least three zones present in order from the upstream side to the downstream side of the exhaust gas flow, and each of these at least three zones is an oxidation catalyst zone or a reduction catalyst zone. In the uppermost layer of an oxidation catalyst zone, the total number of atoms of platinum and palladium is greater than the number of atoms of rhodium; in the upper most layer of a reduction catalyst zone, the number of atoms of rhodium is greater than the total number of atoms of platinum and palladium. The oxidation catalyst zones and the reduction catalyst zones alternate at least twice in the exhaust gas flow direction.

Exhaust gas purification catalyst device

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 &#x3c1;of 0.70 or more, and (iii) has a correlation coefficient &#x3c1;of 0.70 or more.

Exhaust gas-purifying catalyst

An exhaust gas-purifying catalyst material includes first oxide particles having an average particle diameter Dof 1 &#x3bc;m to 95 &#x3bc;m and having an oxygen storage capacity, second oxide particles having an average particle diameter Dof 0.05 &#x3bc;m to 0.5 &#x3bc;m, containing a metal element, and having no oxygen storage capacity, precious metal particles, and acidic oxide particles. The material has a correlation coefficient &#x3c1; of 0.45 or more obtained using first characteristic X-ray intensity for the metal element contained in the second oxide particle, second characteristic X-ray intensity for an element other than oxygen contained in the acidic oxide particle, and third characteristic X-ray intensity for a precious metal element contained in the precious metal particle.

Exhaust gas-purifying catalyst and exhaust gas-purifying catalyst material

An exhaust gas-purifying catalyst includes a substrate, and a catalytic layer facing the substrate and including a precious metal, alumina, an oxygen storage material, and a sulfate of an alkaline-earth metal having an average particle diameter falling within a range of 0.01 to 0.70 &#x3bc;m, the average particle diameter being obtained by observation using a scanning electron microscope. Another exhaust gas-purifying catalyst includes a substrate, and a catalytic layer formed on the substrate using slurry containing a precious metal, alumina, an oxygen storage material, and a sulfate of an alkaline-earth metal having an average particle diameter falling within a range of 0.01 to 0.70 &#x3bc;m, the average particle diameter being obtained by observation using a scanning electron microscope.

An exhaust gas-purifying catalyst according to the present invention includes a substrate, a first catalytic layer facing the substrate and includes at least one precious metal selected from the group consisting of palladium and platinum, and alumina doped with an alkaline-earth metal element, and a second catalytic layer facing the substrate with the first catalytic layer interposed therebetween or intervening between the substrate and the first catalytic layer, the second catalytic layer includes rhodium and alumina doped with the alkaline-earth metal element.

An exhaust gas-purifying catalyst includes a substrate, and a catalytic layer supported by the substrate. The catalytic layer includes a support made of alumina, an oxygen storage material, an alkaline earth metal and/or a compound of alkaline-earth metal selectively supported by a surface of the support and dispersed on the surface of the support, and a precious metal supported by the surface of the support. A ratio of a number of moles of the alkaline-earth metal in the catalytic layer with respect to a volumetric capacity of the exhaust gas-purifying catalyst falls within a range of 0.0004 mol/L to 0.35 mol/L.

Exhaust gas-purifying catalyst, powdery material, and method of manufacturing exhaust gas-purifying catalyst

An exhaust gas purification catalyst includes a substrate, and a first catalyst layer formed on the substrate, the first catalyst layer containing palladium and/or platinum and alumina doped with an alkaline-earth metal element. The exhaust gas purification catalyst has a correlation coefficient &#x3c1;given by the following formula of 0.75 or more: 

Exhaust gas purification catalyst

Decreasing HC emission is made possible. An exhaust gas-purifying catalyst includes a substrate, a hydrocarbon-adsorbing layer covering the substrate, and a catalytic layer covering the hydrocarbon-adsorbing layer. The catalytic layer includes a layered structure of a first catalytic layer including a precious metal and a carrier supporting it, and a second catalytic layer including the same precious metal as the precious metal of the first catalytic layer and a carrier supporting it and having a concentration of the precious metal higher than that in the first catalytic layer.

A hexagonal-cell honeycomb catalyzer is for purifying an exhaust gas. The catalyzer comprising a support that has a plurality of cells and a purification layer that has an HC absorption layer and a three-way catalyst layer. The HC absorption layer is formed on the honeycomb-formed surface of each wall of the support. The three-way catalyst layer is formed on the surface of the HC absorption layer. Provided that the HC absorption layer has a thickness aand the three-way catalyst layer has a thickness bat a thin portion of the purification layer of which thickness is minimum and the HC absorption layer has a thickness aand the three-way catalyst layer has a thickness bat a thick portion of the purification layer of which thickness is maximum, a ratio of a/band a ratio of a/bare both within a range of 1/20 to 5/1.

Hexagonal-cell honeycomb catalyzer for purifying exhaust gas

An exhaust gas purifying catalyst exhibiting high catalytic performance and restraining an amount of noble metals used is provided. An exhaust gas purifying catalyst has a catalyst substrate and a catalyst coating layer formed on the catalyst substrate. The catalyst coating layer has a layered structure including an inside layer containing (a-1) Pd, (a-2) Pt, and (a-3) an inorganic oxide, and an outside layer containing (b-1) a noble metal and (b-2) an inorganic oxide. A part of (a-3) the inorganic oxide carries Pd and Pt so that a weight ratio Pd/Pt is within a range of 8 to 12, whereas the other part of (a-3) the inorganic oxide carries Pd and Pt so that a weight ratio Pd/Pt is within a range of 4 to 6 or within a range of 18 to 22.

Growing community of inventors

Kakegawa, Japan

Yuji Yabuzaki