摘要:
A particulate inorganic mixed oxide comprising: aluminum; zirconium; cerium; lanthanum and an additional element selected from the group consisting of neodymium and praseodymium, wherein the inorganic mixed oxide has at least 80% of primary particles with article diameters of 100 nm or less, and at least a part of the primary particles have an enriched surface region where the additional element is locally increased in a surface layer portion thereof.
摘要:
A particulate inorganic mixed oxide comprising: aluminum; zirconium; cerium; and first and second additional elements each selected from the group consisting of rare earth elements other than cerium and alkaline earth elements, whereina content of aluminum in the inorganic mixed oxide is 60 to 90 at %, in terms of element content, relative to a total amount of elements which form cations in the inorganic mixed oxide ; a content of cerium in the inorganic mixed oxide is 0.4 to 50 at %, in terms of element content, relative to a total amount of zirconium and cerium in the inorganic mixed oxide; a content of a total amount of the first and second additional elements is 1 to 12 at %, in terms of element content, relative to the total amount of the elements which form cations in the inorganic mixed oxide; at least 80% of primary particles of the inorganic mixed oxide have a particle diameter of 100 nm or less; at least a part of the primary particles have an enriched surface region where a content of the second additional element is locally increased in a surface layer portion thereof; and an amount of the second additional element in the enriched surface region is 0.1 to 0.95% by mass, in terms of oxide, relative to a whole amount of the inorganic mixed oxide.
摘要:
An exhaust gas purifying catalyst includes a substrate that defines an exhaust gas passage; a lower catalyst layer formed over the substrate, and an upper catalyst layer formed over the lower catalyst layer. The lower catalyst layer has a lower catalytic precious metal that contains at least one of Pt and Pd, and a lower-layer carrier that supports the lower catalytic precious metal. The upper catalyst layer has an upper catalytic precious metal that contains Rh, and an upper-layer carrier that supports the upper catalytic precious metal. The upper-layer carrier includes an inorganic mixed oxide that contains Ce, Zr, Al, Nd, and at least one element selected from the group consisting of rare earth elements other than Ce and alkaline earth elements. The Nd is unevenly distributed in covering layers that covers surfaces of interior regions within the inorganic mixed oxide.
摘要:
An exhaust gas purifying catalyst includes a substrate that defines an exhaust gas passage; a lower catalyst layer formed over the substrate, and an upper catalyst layer formed over the lower catalyst layer. The lower catalyst layer has a lower catalytic precious metal that contains at least one of Pt and Pd, and a lower-layer carrier that supports the lower catalytic precious metal. The upper catalyst layer has an upper catalytic precious metal that contains Rh, and an upper-layer carrier that supports the upper catalytic precious metal. The upper-layer carrier includes an inorganic mixed oxide that contains Ce, Zr, Al, Nd, and at least one element selected from the group consisting of rare earth elements other than Ce and alkaline earth elements. The Nd is unevenly distributed in covering layers that covers surfaces of interior regions within the inorganic mixed oxide.
摘要:
An exhaust gas purification catalyst includes a composite oxide support, and a precious metal catalyst supported on the composite oxide support. The composite oxide support includes alumina, zirconia, ceria, a first additive element oxide and a second additive element oxide. The first additive element oxide contains an additive element selected from the group consisting of rare earth elements excluding cerium and alkali earth elements. The second additive element oxide contains an additive element selected from the group consisting of rare earth elements excluding cerium and alkali earth elements. In the composite oxide support, alumina is contained in a range of 30 to 40% by mass and zirconia is contained in a range of 36 to 46% by mass.
摘要:
An exhaust gas purification catalyst includes a composite oxide support, and a precious metal catalyst supported on the composite oxide support. The composite oxide support includes alumina, zirconia, ceria, a first additive element oxide and a second additive element oxide. The first additive element oxide contains an additive element selected from the group consisting of rare earth elements excluding cerium and alkali earth elements. The second additive element oxide contains an additive element selected from the group consisting of rare earth elements excluding cerium and alkali earth elements. In the composite oxide support, alumina is contained in a range of 30 to 40% by mass and zirconia is contained in a range of 36 to 46% by mass.
摘要:
A catalyst for purification of exhaust gases, produced by use of a catalyst component A, a catalyst component B, and a binder, the catalyst component A being produced by supporting Rh on a catalyst support for Rh, having a CO2 adsorption amount per unit weight of from 25 μmol·g−1 to 60 μmol·g−1, and having a CO2 adsorption amount per unit specific surface area of from 0.2 μmol·m−2·g1 to 2.3 μmol·m−2·g1, the catalyst having a CO2 adsorption amount per unit weight of from 18 μmol·g−1 to 60 μmol·g−1 and a CO2 adsorption amount per unit specific surface area of from 0.2 μmol·m−2·g1 to 2.5 μmol·m−2·g1, and a ratio of the CO2 adsorption amount per unit weight of the catalyst to the CO2 adsorption amount per unit weight of the catalyst component A [(CO2 adsorption amount of the catalyst/CO2 adsorption amount of the catalyst component A)×100] being 75% or more.
摘要:
A particulate inorganic oxide contains an aluminum oxide, a metal oxide forming no composite oxide with an aluminum oxide, and at least one additional element selected from the group consisting of rare earth elements and alkaline earth elements. In the inorganic oxide, a percentage content of the aluminum oxide to a total amount of aluminum in the aluminum oxide, a metal element in the metal oxide, and the additional element is in a range from 48 at % to 92 at % in terms of element content. At least 80% of primary particles in the inorganic oxide have a particle diameter of 100 nm or smaller. At least a part of the primary particles have a surface concentrated region where a percentage content of the additional element is locally increased in a surface layer part thereof. The content of the additional element in the surface concentrated region to a whole amount of the inorganic oxide is in a range from 0.06% by mass to 0.98% by mass in terms of oxide amount.
摘要:
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.
摘要:
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.