Toyota Jidosha Kabushiki Kaisha

Cataler Corporation

Kabushiki Kaisha Toyota Chuo Kenkyusho

Cataier Corporation

Michihiko Takeuchi

Hirotaka Ori

Satoru Katoh

Hiromasa Suzuki

Masahide Miura

Toshitaka Tanabe

Keiichi Narita

Tatsuya Ohashi

Hiroaki Naito

Yoshinori Saito

Tetsuhiro Hirao

Naoki Takahashi

Tadashi Suzuki

Takaaki Kanazawa

Takeru Yoshida

Satoru Kato

Kazunobu Ishibashi

Masanori Yamato

Ichiro Hachisuka

Minoru Itou

Masaya Kamada

Tetsuya Shinozaki

Kazuhiro Yoshimoto

Yuuji Matsuhisa

Miura Masahide

Saito Yoshinori

Suzuki Hiromasa

Tetsuhio Hirao

Toshitata Tanabe

Itou Minoru

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

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.

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.

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

An exhaust gas-purifying catalyst includes a support provided with one or more through-holes through which exhaust gas flows, and a catalytic layer supported by the support and containing an oxygen storage material. The exhaust gas-purifying catalyst includes a first section to which the exhaust gas is supplied, and a second section to which the exhaust gas having passed through the first section is supplied. The catalytic layer includes a layered structure of a first catalytic layer containing platinum and/or palladium and a second catalytic layer containing rhodium in the first catalytic section and further includes a third layer containing rhodium in the second section. The second section is smaller in oxygen storage material content per unit volumetric capacity than the first section.

Exhaust gas-purifying catalyst

A catalyst for purification of exhaust gas, in which a noble metal is supported on a metal oxide support, has a basic site content of 1 mmol/L-cat or less, as determined on the basis of an amount of COdesorbed per liter of the catalyst as measured by a COtemperature-programmed desorption method.

Catalyst for purification of exhaust gas, and apparatus and method for purification of exhaust gas using the catalyst

The present invention provides an exhaust gas purification catalyst comprising a base material, and a two or more layered catalyst coating layer, formed on the base material, wherein the two or more layers have upper and lower layers, and wherein the upper layer contains a large amount of noble metal per liter of the base material more than that of the lower layer, and the lower layer contains a large amount of an oxygen storage/release material per liter of the base material more than that of the upper layer. This exhaust gas purification catalyst has more excellent HS purifying performance than conventional catalysts while maintaining purifying performance against NOx and the other exhaust gas components.

Catalyst for purifying exhaust gas

Growing community of inventors

Kakegawa, Japan

Michihiko Takeuchi