Cataler Corporation

Daihatsu Motor Company, Ltd.

Toyota Jidosha Kabushiki Kaisha

Denso Corporation

Akimasa Hirai

Kenichi Taki

Satoshi Matsueda

Yuji Yabuzaki

Keiichi Narita

Sho Hoshino

Ichiro Kitamura

Asuka Hori

Hirohisa Tanaka

Mareo Kimura

Isao Tan

Mari Uenishi

Masashi Taniguchi

Masahiro Kusaka

Hiromasa Suzuki

Naoto Miyoshi

Takeru Yoshida

Tomoaki Nakano

Shingo Nakata

Takaaki Kanazawa

Akiya Chiba

Kazunobu Ishibashi

Masakazu Murata

Daisuke Ochiai

Tomohito Mizukami

Satoru Inoda

Yoshiyasu Andoh

An exhaust gas-purifying catalyst includes a support and a catalytic metal supported thereby. The support includes a composite oxide represented by AO.xBCO, wherein A represents at least one of an element having a valence of 1 and an element having a valence of 2, B represents an element having a valence of 3, C represents one or more elements selected from iridium, ruthenium, tantalum, niobium, molybdenum, and tungsten, x represents a numerical value of 1 to 6, and &#x3b1; represents a numerical value greater than 0 and less than 2. The catalytic metal includes one or more precious metals selected from rhodium, palladium, and platinum.

Exhaust gas-purifying catalyst

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.

An exhaust gas-purifying catalyst includes a support and a catalytic metal as one or more precious metals supported by the support. The support includes a composite oxide having a composition represented by a general formula ABCO, wherein A represents one or more elements selected from the group consisting of lanthanum, neodymium, and yttrium, B represents iron or a combination of iron and aluminum, C represents one or more elements selected from the group consisting of iridium, ruthenium, tantalum, niobium, molybdenum, and tungsten, &#x3b1; and &#x3b2; each represents a numerical value within a range of more than 0 and less than 1, and &#x3b1; and &#x3b2; satisfy relational formulae of &#x3b2;&#x3e;&#x3b1; and &#x3b1;+&#x3b2;&#x2266;1.

The exhaust gas-purifying catalyst of the invention contains oxide particles having interdispersed therein A crystallites that are loaded with a noble metal and B crystallites that are not loaded with a noble metal. The A crystallites loaded with a noble metal are composed of an oxide containing at least one of zirconium (Zr) and cerium (Ce). The B crystallites not loaded with a noble metal are composed of a cerium (Ce)-containing oxide which has a higher Ce content (mol %) than the oxide making up the A crystallites. The oxide particles have a specific surface area after 5 hours of heat treatment at 1,150&#xb0; C. in open air of 30 m/g 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

The exhaust gas-purifying catalyst of the invention includes a noble metal, and crystallites that form CZ composite metal particles which serve as a carrier supporting the noble metal and contain at least zirconium (Zr) and cerium (Ce). The CZ composite oxide particles (crystallites) further contain crystal growth-suppressing fine particles which are fine metal particles comprising primarily a metallic element M that melts at 1,500&#xb0; C. or above and which suppress crystal growth by the CZ composite oxide particles. The content of the metallic element M included in the CZ composite oxide particles, expressed in terms of the oxide thereof, is 0.5 mol % or less of the total oxide.

Provided is an exhaust catalyst that exhibits higher NO-reducing activities at the time of engine restart while maintaining its catalytic activities during normal traveling. This invention provides an exhaust cleaning catalyst comprising a substrate and a catalyst coating layer that includes CeO. Catalyst coating layer is constituted in its thickness direction with multiple coating layers. In a top coating layer located at the outermost surface, the CeOcontent in a top coating layer's upstream portion is less than the CeOcontent in a top coating layer's downstream portion; and the CeOcontent in the top coating layer's upstream portion is less than the CeOcontent in a lower coating layer. The CeOcontent per liter of catalyst volume in the entire coating layer is 10 g/L to 30 g/L.

Exhaust cleaning catalyst

Provided is an exhaust cleaning catalyst that exhibits higher NO-reducing activities at the time of engine restart while maintaining its catalytic activities during normal traveling. This invention provides an exhaust cleaning catalyst including a substrate and a catalyst coating layer including CeO. Catalyst coating layer is constituted in its thickness direction with multiple coating layers. In a top coating layer located at the outermost surface, the CeOcontent in a top coating layer's upstream portion is less than the CeOcontent in a top coating layer's downstream portion. In a bottom coating layer near substrate, the CeOcontent in a bottom layer's downstream portion is less than the CeOcontent in a bottom coating layer's upstream portion.

An exhaust cleaning catalyst, with which precious metal sintering is inhibited and which has greater exhaust cleaning abilities, has a substrate and a catalyst coating layer provided on the substrate. The catalyst coating layer has a precious metal that serves as an oxidation and/or reduction catalyst. The precious metal has Rh-containing metal particles in which rhodium (Rh) coexists with a base metal selected among platinum group elements excluding rhodium. The Rh-containing metal particles have an average rhodium content of 0.1% to 5% by mole with the total amount of the base metal and rhodium being 100% by mole.

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 includes first particles of oxygen storage material, second particles of one or more acidic oxides interposed between the first particles, and third particles of one or more precious metal elements interposed between the first particles, wherein a spectrum of a characteristic X-ray intensity for one of constituent elements of the acidic oxide(s) other than oxygen and a spectrum of a characteristic X-ray intensity for one of the precious metal element(s) that are obtained by performing a line analysis using energy-dispersive X-ray spectrometry along a length of 500 nm have a correlation coefficient of 0.70 or more.

An exhaust gas-purifying catalyst includes first particles of oxygen storage material, second particles of one or more rare-earth elements other than cerium and/or compounds thereof interposed between the first particles, and third particles of one or more precious metal elements interposed between the first particles, wherein a spectrum of a characteristic X-ray intensity for one of the rare-earth element(s) and a spectrum of a characteristic X-ray intensity for one of the precious metal element(s) that are obtained by performing a line analysis using energy-dispersive X-ray spectrometry along a length of 500 nm have a correlation coefficient of 0.68 or more.

An excellent oxygen storage capacity is achieved even in the case used for a long period of time under high temperature conditions. An oxygen storage material contains a first particle made of a composite oxide of cerium and zirconium or a composite oxide of cerium, a rare-earth element other than cerium and zirconium, a second particle including a composite oxide of a rare-earth element, an alkaline-earth element and zirconium, and a precious metal. A part of the precious metal forms a solid solution with the composite oxide included in the second particle.

Oxygen storage material

The present invention relates to a catalyst for purifying exhaust gases emitted from the internal combustion engines. The exhaust-gas-purifying catalyst in this invention, comprising: a catalyst support substrate and a plurality of catalyst layers formed on a surface of the catalyst support substrate and having an exterior-surface layer for forming a surface of the plural catalyst layers, and the exterior-surface layer including a loading layer formed by fireproof inorganic oxide; at least one catalytic metal selected from the group consisting of platinum, palladium and rhodium, and supported on the loading layer; stabilized zirconia loaded on the loading layer; and cerium-zirconium composite oxide loaded on the loading layer, and the stabilized zirconia including zirconia and oxide formed by at least one additive member selected from the group consisting of yttrium, neodymium, praseodymium and lanthanum. The durability of the exhaust-gas-purifying catalyst was improved by having the stabilized zirconia and cerium-zirconium composite oxide in the exterior-surface layer.

Growing community of inventors

Kakegawa, Japan

Akimasa Hirai