Cataler Corporation

Toyota Jidosha Kabushiki Kaisha

Kabushiki Kaisha Toyota Chuo Kenkyusho

Akiya Chiba

Akira Morikawa

Akihiko Suda

Hiromasa Suzuki

Masahide Miura

Toshitaka Tanabe

Isao Chinzei

Kosuke Iizuka

Kae Konishi

Takeru Yoshida

Hirotaka Ori

Takaaki Kanazawa

Mitsuyoshi Okada

Isao Naito

Motoya Abe

Naoki Takahashi

Hirohisa Tanaka

Naoto Miyoshi

Satoshi Matsueda

Akimasa Hirai

Keiichi Narita

Mareo Kimura

Yuki Aoki

Oji Kuno

Yoshinori Saito

Isao Tan

Mari Uenishi

Takeshi Nobukawa

Kazunobu Ishibashi

Masashi Taniguchi

Daisuke Ochiai

Kae Yamamura

Masanao Sato

Shunsuke Haga

Hiroki Nagashima

Ryuta Fujii

A ceria-zirconia-based composite oxide containing a composite oxide of ceria and zirconia is provided, in which primary particles having a particle diameter of 1.5 to 4.5 &#x3bc;m account for, on a particle number basis, at least 50% of all primary particles in the ceria-zirconia-based composite oxide, and the molar ratio of cerium to zirconium in the ceria-zirconia-based composite oxide is between 43:57 and 55:45.

Ceria-zirconia-based composite oxide and method for producing same, and exhaust gas purification catalyst including ceria-zirconia-based composite oxide

The object of the present invention is to provide an exhaust gas purifying catalyst that can achieve high purification performance while suppressing HS emissions. The object is solved by an exhaust gas purifying catalyst in which the top layer of a catalyst coating layer comprises a ceria-zirconia composite oxide having a pyrochlore-type ordered array structure, in which the ceria-zirconia composite oxide contains at least one additional element selected from the group consisting of praseodymium, lanthanum, and yttrium at 0.5 to 5.0 mol % in relation to the total cation amount, and the molar ratio of (cerium+additional element):(zirconium) is within the range from 43:57 to 48:52.

Exhaust gas purifying catalyst

An exhaust gas purifying catalyst with an excellent effect of suppressing deterioration due to aggregation of a noble metal catalyst during endurance at high temperature, and a production method therefor. The method for producing the exhaust gas purifying catalyst that has a porous carrier and a noble metal catalyst supported thereon includes: preparing the porous carrier that contains alumina-ceria-zirconia composite oxide particles and has physical property values, after subjected to baking at 900&#xb0; C. for 5 hours, of a pore diameter of the particles in the range of 2 to 20 nm, a specific surface area of the particles in the range of 75 to 115 m/g, a crystallite size of a ceria-zirconia composite oxide contained in the particles in the range of 4 to 6 nm, and a bulk density of the particles in the range of 0.5 to 0.9 cm/g, and bringing a noble metal chemical solution having an aggregate of platinum or the like with a grain size adjusted to less than or equal to 1 nm with the use of a platinum nitric acid solution or the like, into contact with the porous carrier, so that the noble metal catalyst is supported on the porous carrier.

Exhaust gas purifying catalyst and method for producing the same

The object of the present invention is to provide a high-performance exhaust gas purifying catalyst that can achieve oxygen absorption/release capacity and NOx purification performance. The object is solved by an exhaust gas purifying catalyst, which comprises a ceria-zirconia composite oxide having a pyrochlore-type ordered array structure in the upstream part of the catalyst coating layer, in which the ceria-zirconia composite oxide contains at least one additional element selected from the group consisting of praseodymium, lanthanum, and yttrium at 0.5 to 5.0 mol % of the total cation amount, and has a molar ratio of (cerium+the additional element):(zirconium) of 43:57 to 48:52.

A ceria-zirconia composite oxide includes at least one of lanthanum, yttrium, and praseodymium. A rate of a total content of the at least one rare earth element to a total content of cerium and zirconium is 0.1 at % to 4.0 at %. A content of the rare earth element present in near-surface regions, which are at a distance of less than 50 nm from surfaces of primary particles of the ceria-zirconia composite oxide, accounts for 90 at % or more of the total content of the rare earth element. An average particle size of the primary particles of the ceria-zirconia composite oxide is 2.2 &#x3bc;m to 4.5 &#x3bc;m. After a predetermined durability test, the intensity ratio I(14/29) of a diffraction line at 2&#x3b8;=14.5&#xb0; to a diffraction line at 2&#x3b8;=29&#xb0; and the intensity ratio I(28/29) of a diffraction line at 2&#x3b8;=28.5&#xb0; to the diffraction line at 2&#x3b8;=29&#xb0; respectively satisfy the following conditions:(14/29)&#x2265;0.02, and(28/29)&#x2264;0.08.

Ceria-zirconia composite oxide, method for producing the same, and catalyst for purifying exhaust gas using the ceria-zirconia composite oxide

A ceria-zirconia-based composite oxide including a composite oxide containing ceria and zirconia, wherein the ceria-zirconia-based composite oxide contains at least one member selected from the group consisting of praseodymium, lanthanum, and yttrium in an amount of 0.5 to 5.0 mol % relative to a total amount of the cations contained in the ceria-zirconia-based composite oxide, where the ratio of the content of both cerium and the at least one member selected from the group consisting of praseodymium, lanthanum, and yttrium in the ceria-zirconia-based composite oxide to the content of zirconium therein ([cerium and the at least one member selected from the group consisting of praseodymium, lanthanum, and yttrium]:[zirconium]) is in the range of 43:57 to 48:52 by mole ratio.

Ceria-zirconia-based composite oxide and method for producing same, and catalyst for exhaust gas purification including ceria-zirconia-based composite oxide

A ceria-zirconia base composite oxide contains a composite oxide of ceria and zirconia. In the ceria-zirconia base composite oxide, a content ratio between cerium and zirconium in the composite oxide is in a range from 43:57 to 48:52 in terms of molar ratio ([cerium]:[zirconium]). An intensity ratio of a diffraction line at 2&#x3b8;=14.5&#xb0; to a diffraction line at 2&#x3b8;=29&#xb0; {I(14/29) value} and an intensity ratio of a diffraction line at 2&#x3b8;=28.5&#xb0; to the diffraction line at 2&#x3b8;=29&#xb0; {I(28/29) value}, which are calculated from an X-ray diffraction pattern obtained by an X-ray diffraction measurement using CuKa after heating under a temperature condition of 1100&#xb0; C. in air for 5 hours, respectively satisfy the following conditions: I(14/29) value&#x2267;0.015, and I(28/29) value&#x2266;0.08.

Ceria-zirconia base composite oxide, method for producing the same, and catalyst for purification of exhaust gas using the ceria-zirconia base composite oxide

An exhaust gas-purifying catalyst whose activity is less prone to be decreased even in the case where used in a high-temperature atmosphere containing oxygen at a high concentration can be realized. The catalytic layer of the catalyst includes an oxide particle, a simple oxide of alkaline-earth element or rare-earth element, and alumina and/or aluminum hydroxide. The oxide particle contains an oxide of rare-earth element and/or zirconium, a composite oxide and a precious metal. The composite oxide contains an alkaline-earth element and at least one of the rare-earth element and zirconium. The composite oxide and a part of the precious metal form a solid solution.

Exhaust gas-purifying catalyst and method of manufacturing the same

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

A rhodium-loading solution characterized by comprising rhodium atoms and an organic base in a molar ratio of 1:0.5-35.

Rhodium-loading solution and rhodium catalyst prepared using the same

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Kakegawa, Japan

Akiya Chiba