Abstract: A regeneration apparatus comprises a heater 2 which heats a catalyst 1 at the time of stopping fuel supply to an engine, a pump 4 which supplies an oxidizing gas or a reducing gas to the heated catalyst 1 and a switching valve 3. In the oxidizing step, catalytic poisons, for example hydrocarbon, which are absorbed on a noble metal are oxidized and removed. The particles of the noble metal become oxidized particles as pure oxide and the like. After the oxidizing step, the reducing step is carried out. In the reducing step, particles of the noble metal are reduced and re-dispersed on the support simultaneously and as a result, the particles of the noble metal become fine. Thus, a deteriorated catalyst can be regenerated without interrupting the use of catalyst and also without deteriorating the drivability.

Abstract: 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.

Abstract: An exhaust gas purification system includes: a catalyst (3) provided in an exhaust gas passage of an internal combustion engine (1) and having a carrier containing a basic oxide and platinum carried on the carrier; a catalyst (4) for purifying NOx; and oxygen supply means (2).

Abstract: 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.

Abstract: A regeneration apparatus comprises a heater 2 which heats a catalyst 1 at the time of stopping fuel supply to an engine, a pump 4 which supplies an oxidizing gas or a reducing gas to the heated catalyst 1 and a switching valve 3. In the oxidizing step, catalytic poisons, for example hydrocarbon, which are absorbed on a noble metal are oxidized and removed. The particles of the noble metal become oxidized particles as pure oxide and the like. After the oxidizing step, the reducing step is carried out. In the reducing step, particles of the noble metal are reduced and re-dispersed on the support simultaneously and as a result, the particles of the noble metal become fine. Thus, a deteriorated catalyst can be regenerated without interrupting the use of catalyst and also without deteriorating the drivability.

Abstract: 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.

Abstract: An exhaust gas purification system includes: at least two catalysts (1a, 1b) disposed in parallel with each other on an exhaust gas passage of an internal combustion engine (3) and having a carrier containing a basic oxide and platinum carried on the carrier; and oxygen supply means (2) for supplying oxygen to the catalysts (1a, 1b).

Abstract: 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.

Abstract: A catalyst for purification of exhaust gas, comprising: a material (A) which can release a noble metal at a high temperature; and a material (B) which contains a composite oxide of zirconia and/or alumina and at least one element selected from the group consisting of alkaline earth metal elements, rare earth elements and group 3A elements, and which receives the noble metal released from the material (A) at the high temperature.

Abstract: An exhaust gas purification system includes: a catalyst (3) provided in an exhaust gas passage of an internal combustion engine (1) and having a carrier containing a basic oxide and platinum carried on the carrier; a catalyst (4) for purifying NOx; and oxygen supply means (2).

Abstract: A catalyst for purifying exhaust gases includes a porous support, at least one catalyst ingredient selected from Pt and Pd, and additional ingredients including (1) at least two rare-earth elements including La, (2) at least one rare-earth element including La and at least one transition element selected from Fe, Ni, Co and Mn, (3) at least two alkali metals, (4) at least one alkali metal and at least one rare-earth element including La, (5) at least one alkali metal and at least one transition element selected from Fe, Ni, Co and Mn, (6) at least two alkaline-earth metals, (7) at least one alkaline-earth metal and at least one rare-earth element including La, or (8) Ba, Li, La, Ce and Zr. A process for purifying an exhaust gas, by contacting the catalyst with an exhaust gas, is also provided.