Abstract: A catalyst layer includes: a first mixed oxide particle component 4 which contains Ce and Rh 8 and in which Rh is partially exposed at particle surfaces; and a second mixed oxide particle component 5 containing Ce, Zr, and a rare earth metal except Ce. The particle size distribution of the first mixed oxide particle component 4 has a peak in the particle size range from 100 nm to 300 nm, both inclusive. The particle size distribution of the second mixed oxide particle component 5 has a peak in a particle size range larger than the particle size range in which the first mixed oxide particle component 4 has the peak. At least part of particles of the first mixed oxide particle component 4 is attached to at least part of particles of the second mixed oxide particle component 5.

Abstract: A catalyst layer includes: a first mixed oxide particle component 4 which contains Ce and Rh 8 and in which Rh is partially exposed at particle surfaces; and a second mixed oxide particle component 5 containing Ce, Zr, and a rare earth metal except Ce. The particle size distribution of the first mixed oxide particle component 4 has a peak in the particle size range from 100 nm to 300 nm, both inclusive. The particle size distribution of the second mixed oxide particle component 5 has a peak in a particle size range larger than the particle size range in which the first mixed oxide particle component 4 has the peak. At least part of particles of the first mixed oxide particle component 4 is attached to at least part of particles of the second mixed oxide particle component 5.

Abstract: Disclosed is an exhaust gas purifying catalyst, which comprises a catalyst layer formed on a honeycomb-shaped support. The catalyst layer is formed by mixing a catalyst powder (A) consisting of a composite oxide (RhZrCeNdO) which contains at least Ce, Zr, and a catalytic noble metal composition, and a catalyst powder (B) consisting of a Zr-based oxide (RhZrXO) which contains at least Zr and has Rh existing on a surface thereof. A ratio (RhZrXO/RhZrCeNdO) of a mass of the catalyst powder (B) to a total mass of the catalyst powder (A) and the catalyst powder (B) may be set in the range of 1 to 50%. Further, the catalyst powder (B) may consist of a composite oxide which contains Zr as a primary component, a rare-earth metal except Ce, and Rh. The exhaust gas purifying catalyst of the present invention can provide enhanced exhaust gas conversion efficiency.

Abstract: An upstream catalyst and a downstream catalyst are disposed in an exhaust passage of an engine. The downstream catalyst contains in the same catalyst layer thereof. Rh-doped CeZrNd mixed oxide particles on which Rh is supported and active alumina particles on which Pt is supported. The upstream catalyst is a three-way catalyst containing an oxygen storage component having a lower oxygen storage capacity than the Rh-doped CeZrNd mixed oxide.

Abstract: Disclosed is an exhaust gas purifying catalyst, which comprises a CeZr-based composite oxide capable of maintaining a hollow structure to ensure an oxygen absorbing/releasing capability, even after being exposed to high-temperature exhaust gas. The exhaust gas purifying catalyst comprises a honeycomb-shaped substrate, and a catalyst layer formed on a surface of the substrate. The catalyst layer contains a composite oxide which includes cerium (Ce) and zirconium (Zr) and has a hollow structure, and a catalytic metal supported by the composite oxide. The composite oxide having the hollow structure includes, in a state after being subjected to a thermal aging in Air at 1000° C. for 24 hours, a particle with a shape having an outer diameter of 750 to 1000 nm and a shell thickness of 80 to 120 nm.

Abstract: An exhaust gas purification catalyst comprises: an oxygen storage component constituted by a mixed oxide containing cerium and zirconium; and a catalytic metal carried on the oxygen storage component. The oxygen storage component is in the form of hollow secondary particles each formed so that primary particles of an average particle size of less than 10 nm cohere into a shell.

Abstract: An exhaust gas purification catalyst includes a catalyst layer formed on a support. The catalyst layer contains Ce-containing oxide particles having an oxygen storage/release capacity and a catalytic metal. The catalyst layer further contains a large number of iron oxide particles of 300 nm diameter or less that are dispersed therein and are in contact with the Ce-containing oxide particles. When observed by electron microscopy, the proportion of the area of iron oxide particles of 300 nm diameter or less to the total area of all of iron oxide particles in the catalyst layer is 30% or more.

Abstract: An exhaust gas purifying catalyst comprising: a honeycomb-like substrate disposed in an exhaust passage for an engine; and a catalytic layer formed on a cell wall of said substrate, said catalytic layer including a mixed oxide which contains Ce (cerium) and Zr (zirconium), and retains a catalytic noble metal in such a manner that said noble metal atoms are located at crystal lattice points or between the lattice points of the mixed oxide, wherein said mixed oxide includes a first mixed oxide containing CeO2 in a mass greater than that of ZrO2, and a second mixed oxide containing ZrO2 in a mass greater than that of CeO2.

Abstract: Disclosed is an exhaust gas purifying catalyst system, which comprises an upstream catalyst disposed in an exhaust gas passage of an engine at a position on an upstream side with respect to a direction of an exhaust gas stream, and a downstream catalyst disposed in the exhaust gas passage at a position on a downstream side with respect to the direction of the exhaust gas stream. In the exhaust gas purifying catalyst system, the downstream catalyst includes a cerium (Ce)-containing rhodium-doped composite oxide and an Ni component, and the upstream catalyst includes a cerium (Ce)-containing composite oxide other than the rhodium-doped composite oxide, and a Ni component. A ratio of Ni to CeO2 in the upstream catalyst is in the range of 15 to 20 mass %, and a ratio of Ni to CeO2 in the downstream catalyst is in the range of 10 to 60 mass %. The exhaust gas purifying catalyst system of the present invention can reduce an amount of H2S emission while achieving high purification performance.

Abstract: Catalytic converter comprises a carrier having exhaust gas passages therein, a lower catalytic layer coated over the carrier and comprising hollow oxide powder loaded with catalytic metal, and an upper catalytic layer coated over the lower catalytic layer, directly exposed to exhaust gas flowing in the exhaust gas passages and comprising solid oxide powder loaded with catalytic metal. The hollow oxide powder may be ceria or alumina base oxide. Further it may be mixed oxide such as Ce—Zr mixed oxide or La contained alumina as well.

Abstract: In an exhaust gas purification catalyst that contains an oxygen storage component containing Ce and Zr, alumina and a catalytic metal, a plurality of primary particles of the oxygen storage component and a plurality of primary particles of the alumina agglomerate to form each of mixed oxide particles and the catalytic metal includes Pd doped in the oxygen storage component particles to constitute each of the oxygen storage component particles with Ce and Zr and exposed at the surfaces of the oxygen storage component particles and Pd adhered to the surfaces of the oxygen storage component particles and the surfaces of the alumina particles.

Abstract: The present invention relates to an exhaust gas purification catalytic material containing: (a) a mixed oxide containing Ce and Zr for storing and releasing oxygen; and (b) a precious metal catalyst made of one or more kinds of precious metals. The precious metal catalyst comprises a first precious metal catalyst component placed between atoms, at crystal lattice points and/or at oxygen defect sites of the mixed oxide and a second precious metal catalyst component loaded on the surface of the mixed oxide, thereby improving the thermal resistance, oxygen storage capacity and exhaust gas conversion performance of the catalytic material.

Abstract: An upstream catalyst and a downstream catalyst are disposed in an exhaust passage of an engine. The downstream catalyst contains in the same catalyst layer thereof. Rh-doped CeZrNd mixed oxide particles on which Rh is supported and active alumina particles on which Pt is supported. The upstream catalyst is a three-way catalyst containing an oxygen storage component having a lower oxygen storage capacity than the Rh-doped CeZrNd mixed oxide.

Abstract: In an exhaust gas purification catalyst comprising a honeycomb support and a catalytic layer that is formed on wall surfaces of each cell of the honeycomb support and contains active alumina and a mixed oxide containing Ce, Zr and Nd and doped with catalytic precious metal, the mixed oxide has a CeO2/ZrO2 mass ratio of 1.4 or more and the ratio of Nd2O3/(CeO2+ZrO2+Nd2O3) in the mixed oxide is 20 mass % or less.

Abstract: Disclosed is an exhaust gas purifying catalyst, which comprises a catalyst layer formed on a honeycomb-shaped support. The catalyst layer is formed by mixing a catalyst powder (A) consisting of a composite oxide (RhZrCeNdO) which contains at least Ce, Zr, and a catalytic noble metal composition, and a catalyst powder (B) consisting of a Zr-based oxide (RhZrXO) which contains at least Zr and has Rh existing on a surface thereof. A ratio (RhZrXO/RhZrCeNdO) of a mass of the catalyst powder (B) to a total mass of the catalyst powder (A) and the catalyst powder (B) may be set in the range of 1 to 50%. Further, the catalyst powder (B) may consist of a composite oxide which contains Zr as a primary component, a rare-earth metal except Ce, and Rh. The exhaust gas purifying catalyst of the present invention can provide enhanced exhaust gas conversion efficiency.

Abstract: Disclosed is an exhaust gas purifying catalyst, which comprises a CeZr-based composite oxide capable of maintaining a hollow structure to ensure an oxygen absorbing/releasing capability, even after being exposed to high-temperature exhaust gas. The exhaust gas purifying catalyst comprises a honeycomb-shaped substrate, and a catalyst layer formed on a surface of the substrate. The catalyst layer contains a composite oxide which includes cerium (Ce) and zirconium (Zr) and has a hollow structure, and a catalytic metal supported by the composite oxide. The composite oxide having the hollow structure includes, in a state after being subjected to a thermal aging in Air at 1000° C. for 24 hours, a particle with a shape having an outer diameter of 750 to 1000 nm and a shell thickness of 80 to 120 nm.

Abstract: An exhaust gas purifying catalyst includes a carrier and a catalyst layer provided on the carrier. The catalyst layer includes active Al2O3 on which a noble metal is carried, an oxygen storage agent on which Rh is carried, Al2O3 coated with ZrO2 on which Rh is carried, and a binder material.

Abstract: An exhaust gas purification catalyst comprises an oxygen storage component constituted by a mixed oxide containing cerium and zirconium, and a catalytic metal and a NOx storage component are carried on the oxygen storage component. The oxygen storage component is in the form of porous secondary particles in each of which primary particles of an average particle size of less than 10 nm cohere to form fine pores inside each said secondary particle.

Abstract: An exhaust gas purification catalyst comprises: an oxygen storage component constituted by a mixed oxide containing cerium and zirconium; and a catalytic metal carried on the oxygen storage component. The oxygen storage component is in the form of hollow secondary particles each formed so that primary particles of an average particle size of less than 10 nm cohere into a shell.

Abstract: An exhaust gas purifying catalyst comprising: a honeycomb-like substrate disposed in an exhaust passage for an engine; and a catalytic layer formed on a cell wall of said substrate, said catalytic layer including a mixed oxide which contains Ce (cerium) and Zr (zirconium), and retains a catalytic noble metal in such a manner that said noble metal atoms are located at crystal lattice points or between the lattice points of the mixed oxide, wherein said mixed oxide includes a first mixed oxide containing CeO2 in a mass greater than that of ZrO2, and a second mixed oxide containing ZrO2 in a mass greater than that of CeO2.