Toyota Jidosha Kabushiki Kaisha

Cataler Corporation

Kabushiki Kaisha Toyota Chuo Kenkyusho

Kabushiki Kaisha Toyota Chuo

Cataier Corporation

Toshitaka Tanabe

Masahide Miura

Hiromasa Suzuki

Akira Morikawa

Akihiko Suda

Isao Chinzei

Hirotaka Ori

Yoshinori Saito

Naoki Takahashi

Tetsuhiro Hirao

Takeru Yoshida

Keiichi Narita

Tatsuya Ohashi

Satoru Katoh

Akiya Chiba

Michihiko Takeuchi

Kosuke Iizuka

Hiroaki Naito

Yuki Aoki

Miho Hatanaka

Yasutaka Nagai

Kae Konishi

Tadashi Suzuki

Nobuyuki Takagi

Kazuhiko Dohmae

Mitsuyoshi Okada

Yasuo Ikeda

Shinichi Matsumoto

Hideo Sobukawa

Oji Kuno

Akemi Sato

Takaaki Kanazawa

Toshio Yamamoto

Mamoru Ishikiriyama

Naoki Kumatani

Takahiro Suzuki

Hiroaki Hayashi

Masahiro Sugiura

Shingo Sakagami

Takeshi Nobukawa

Atsushi Tanaka

Daisuke Ochiai

Kae Yamamura

Kenichirou Suzuki

Takahiro Hayashi

Masaaki Kawai

Kimitoshi Sato

Masanori Yamato

Yoshihiro Goto

Megumi Sasaki

Masanao Sato

Miura Masahide

Saito Yoshinori

Suzuki Hiromasa

Tetsuhio Hirao

An object of the present invention is to provide an exhaust gas purification catalyst which can exhibit sufficient purification performance even under a high Ga condition. The present invention relates to an exhaust gas purification catalyst comprising a substrate and a catalyst coating layer formed on the substrate, wherein the catalyst coating layer comprises catalyst particles, the catalyst coating layer having an upstream region extending by 40 to 60% of the entire length of the substrate from an upstream end of the catalyst in the direction of an exhaust gas flow and a downstream region corresponding to the remainder portion of the catalyst coating layer, the composition of the catalyst particle of the upstream region being different from that of the downstream region. The downstream region in the direction of an exhaust gas flow has a structure where a void is included in a large number, and furthermore high-aspect-ratio pores having an aspect ratio of 5 or more account for a certain percentage or more of the whole volume of voids. Thus, the exhaust gas purification catalyst exhibits enhanced purification performance.

Exhaust gas purification catalyst

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 problem of the present invention is to provide an exhaust gas purification catalyst which can exhibit sufficient purification performance under a high Ga condition while having a resistance to stress such as high-temperature and poisonous substances. The present invention relates to an exhaust gas purification catalyst comprising two or more catalyst coating layers on a substrate, wherein a lower catalyst coating layer that is present lower with respect to an uppermost catalyst coating layer has a structure where a large number of voids are included and high-aspect-ratio pores having an aspect ratio of 5 or more account for a certain proportion or more of the whole volume of voids, thereby to improve gas diffusivity in the lower catalyst coating layer.

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 lower layer of the 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

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.

An object of the present invention is to provide an exhaust gas purification catalyst which can exhibit high durability and warm-up performance. The present invention relates to an exhaust gas purification catalyst comprising a substrate and a catalyst coating layer formed on the substrate, wherein the catalyst coating layer comprises catalyst particles, the catalyst coating layer having an upstream region extending by 40 to 60% of the entire length of the substrate from an upstream end of the catalyst in the direction of an exhaust gas flow and a downstream region corresponding to the remainder portion of the catalyst coating layer, the composition of the catalyst particle of the upstream region being different from that of the downstream region. The upstream region in the direction of an exhaust gas flow has a structure where a void is included in a large number, and furthermore high-aspect-ratio pores having an aspect ratio of 5 or more account for a certain percentage or more of the whole volume of voids. Thus, the exhaust gas purification catalyst exhibits enhanced purification performance.

When the amount of coating is increased in a two-layer catalyst or the like containing two noble metals in respective different layers, gas diffusivity in the catalyst and use efficiency of a catalytic active site are reduced to thereby reduce purification performance. In view of this, an organic fiber having a predetermined shape is used as a pore-forming material in formation of an uppermost catalyst coating layer of a multi-layer catalyst, to thereby form an uppermost catalyst coating layer having a high-aspect-ratio pore excellent in connectivity and therefore excellent gas diffusivity.

The present invention is directed to address the following problem: in an exhaust gas purification catalyst comprising a dual catalyst of a combination of a startup catalyst and an underfloor catalyst, reduction in the gas diffusivity of the underfloor catalyst results in reduction in the use efficiency of a catalytic active site, resulting in reduction in purification performance. The present invention relates to an exhaust gas purification catalyst comprising a dual catalyst of a combination of a startup catalyst and an underfloor catalyst having a catalyst coating where a large number of voids are included, wherein high-aspect-ratio pores having an aspect ratio of 5 or more account for a certain rate or more of the whole volume of the voids, to thereby enhance the purification performance of the catalyst.

An oxygen storage material comprises three pyrochlore-type composite oxides which are a ceria-zirconia composite oxide, a lanthana-zirconia composite oxide, and a ceria-zirconia-lanthana composite oxide, and which coexist together, wherein the oxygen storage material contains:

Oxygen storage material and method of 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 catalyst for purification of exhaust gas, wherein a substrate and a catalyst coat layer which is formed on a surface of the substrate and which comprises catalyst particles, wherein the catalyst coat layer has an average thickness in a range of 25 to 160 &#x3bc;m, and a void fraction in a range of 50 to 80% by volume as measured by a weight-in-water method, 0.5 to 50% by volume of all voids in the catalyst coat layer consist of high-aspect ratio pores which have equivalent circle diameters in a range of 2 to 50 &#x3bc;m in a cross-sectional image of a cross-section of the catalyst coat layer which the cross-section is perpendicular to a flow direction of exhaust gas in the substrate, and which have aspect ratios of 5 or higher, and the high-aspect ratio pores have an average aspect ratio in a range of 10 to 50.

Catalyst for purification of exhaust gas, method for producing the same, and method for purification of exhaust gas using the same

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

An exhaust gas purification catalyst having a base and a catalytic coating layer formed thereon includes an alumina support, a platinum-group metal, an iron oxide-zirconia-based composite oxide, and a lanthanoid oxide in the same catalytic coating layer.

Exhaust gas purification catalyst for motor vehicle

Provided is an exhaust gas control catalyst including: a substrate (); and a catalyst layer () that is arranged on the substrate, in which the catalyst layer () includes a palladium region () that contains palladium, aluminum oxide, ceria-zirconia solid solution, and a composite oxide of lanthanum, iron, and zirconium, and a rhodium region () that is arranged adjacent to the palladium region along a plane direction of the catalyst layer and contains rhodium, aluminum oxide, and ceria-zirconia solid solution.

Exhaust gas control catalyst

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Nagakute, Japan

Toshitaka Tanabe