Toyota Jidosha Kabushiki Kaisha

Kabushiki Kaisha Toyota Chuo Kenkyusho

Yasuo Ikeda

Masahide Miura

Toshitaka Tanabe

Nobuyuki Takagi

Yasutaka Nagai

Kazuhiko Dohmae

Shinichi Matsumoto

Miho Hatanaka

Toshio Yamamoto

Hiroshi Hirayama

Akihiko Suda

Hirohito Hirata

Hideo Sobukawa

Mareo Kimura

Masahiro Sugiura

Tadashi Suzuki

Yoshio Ukyo

Toshio Kandori

Ichiro Hachisuka

Riemi Tanizawa

Sinji Tsuji

A metal oxide catalyst carrier particle has a center portion and an outer skin portion each containing a first metal oxide and a second metal oxide. The center portion and the outer skin portion are different in composition. The mole fraction of the metal of the first metal oxide is higher in the center portion than in the outer skin portion and the mole fraction of the metal of the second metal oxide is higher in the outer skin portion than in the center portion. The second metal oxide is selected from the group consisting of rare earth oxides, except for ceria, and alkali earth metal oxides. In addition, platinum is supported on the metal oxide catalyst carrier particle, thus forming an exhaust gas purification catalyst.

Metal oxide catalyst carrier particle and exhaust gas purification catalyst

An exhaust gas purification system includes: a catalyst () provided in an exhaust gas passage of an internal combustion engine () and having a carrier containing a basic oxide and platinum carried on the carrier; a catalyst () for purifying NOx; and oxygen supply means ().

Exhaust gas purification system for internal combustion engine

A catalyst for purification of exhaust gas in which a noble metal is supported on a metal-oxide support wherein, in a oxidation atmosphere, the noble metal exists on the surface of the support in high oxidation state, and the noble metal binds with a cation of the support via an oxygen atom on the surface of the support to form a surface oxide layer and, in a reduction atmosphere, the noble metal exists on the surface of the support in a metal state, and an amount of noble metal exposed at the surface of the support, measured by CO chemisorption, is 10% or more in atomic ratio to a whole amount of the noble metal supported on the support.

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

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

A catalyst for purifying exhaust of an internal combustion engine is prepared by mixing first powders in which at least Pt is loaded on a first support and second powders in which at least Rh is loaded on a second support and loading NO occluding material, for example an alkaline-earth metal, alkali metal or rare-earth metal, at least on the first support. In such catalyst, the second support is made of a stabilized zirconia stabilized by alkaline-earth metal or rare-earth element. The second support, having been become alkaline by the alkaline-earth metal or the rare-earth element, is excellent in absorbing performance of the steam (H O), so that the steam reforming reaction by Rh advances sufficiently. Therefore, the created hydrogen greatly contributes to the reduction of NO and to the sulfur poisoning prevention of the NO occluding material. Also, the oxidizing ability of Pt is maintained high, Rh sufficiently exhibits the steam reforming reaction activity and the sulfur poisoning of NO occluding material is restrained. An exhaust gas from an internal combustion engine is combusted where mixed gas of rich atmosphere containing excessive fuel is supplied to mixed gas of lean atmosphere containing excessive oxygen like a pulse. The exhaust gas is then introduced to the catalyst wherein the exhaust gas is purified.

Catalyst for purifying exhaust gas and exhaust gas purifying method

An exhaust gas purifying catalyst is formed of a first powder formed of porous particles supporting rhodium (Rh), and a second powder formed of porous particles supporting platinum (Pt) and a nitrogen oxides (NOX)-adsorbing material. The second powder and the first powder are present in a mixed state. In this catalyst, Rh is supported apart from Pt and the NOx adsorbent, so that reduction of the oxidizing performance of Pt is prevented, and so that the problems of poor compatibility between Rh and the NOx adsorbent is eliminated. The catalyst therefore maintains high NOx removing rate not only during an initial period but also after the endurance test.

Exhaust gas purifying catalyst and exhaust gas purifying method

A solid solution particle of oxides contains a solid solution of oxides in which one oxide is dissolved into the other oxide, and in which the degree of dissolution of one oxide into the other oxide is not less 50%, and in which an average diameter of crystallite is not more than 100 nm. The solid solution particle of oxides has small average diameter of a crystallite and large specific surface area, and it improves capacities such as an oxygen storage ability due to high degree of dissolution. A catalyst for purifying exhaust gases has excellent purifying performance by employing the solid solution comprising ceria and zirconia which has large OSC and high oxygen adsorption and discharge speed.

Solid solution particle of oxides, a process for producing the same and

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Toyota, Japan

Yasuo Ikeda