Abstract: To provide a catalyst composition containing a novel perovskite-type composite oxide which permits reversible entrance and exit of noble metals, a catalyst composition is prepared so as to contain a perovskite-type composite oxide represented by the general formula (1): AxA?wByB?(1-y-z)NzO3±???(1) (wherein A represents at least one element selected from alkaline earth metals; A? represents at least one element selected from rare earth elements; B represents a tetravalent rare earth element; B? represents at least one element selected from transition elements (excluding tetravalent rare earth elements, Rh, Pd and Pt); N represents at least one element selected from Rh, Pd and Pt; x and w represent an atomic ratio satisfying the following relations: 0.8?x+w?1.3 (0.8?x?1.3, 0?w?0.4); y represents an atomic ratio satisfying the following relation: 0<y<1.0; z represents an atomic ratio satisfying the following relation: 0<z?0.5; and ? represents an oxygen excess or deficiency amount).

Abstract: An exhaust gas-purifying catalyst is less prone to cause a decrease in its activity even when used in a high temperature atmosphere containing oxygen at a high concentration. The exhaust gas-purifying catalyst includes a composite oxide and Pd or a second solid solution of a composite and Rh and/or Pt. The first and second solid solutions have perovskite structure and are represented by ABO3 and CDO3, respectively. The composite oxide catalyst is supported by a composite oxide support including a composite oxide of spinel structure represented by EF2O4 or a composite oxide represented by GAl12O19. A and B represent a rare-earth element and a transition element, respectively. C and G represent an alkaline-earth element. D represents one or more of Ti, Zr, Hf and Ce. E represents an alkaline-earth element and/or a transition element. F represents one or more of Al, Mg and transition elements.

Abstract: An exhaust gas-purifying catalyst includes a support and a catalyst active component including at least one noble metal supported by at least a portion of the support. The support includes a stabilized zirconia containing at least one stabilizing element selected from rare earth elements and alkaline earth elements. 20 to 80% by weight of a total amount of the active component is supported in the support in a form of solid solution with the stabilized zirconia, and 80 to 20% by weight of a total amount of the active component is supported on a surface of at least a portion of the support.

Abstract: An exhaust gas-purifying catalyst (1) contains a rare-earth element, an alkaline-earth element, zirconium and a precious metal, wherein an atomic ratio of the alkaline-earth element with respect to a sum of the rare-earth element and the zirconium is 10 atomic % or more, a part of the rare-earth element and a part of zirconium form a composite oxide with at least a part of the alkaline-earth element, and the composite oxide and a part of the precious metal form a solid solution.

Abstract: An object of the present invention is to provide a catalyst composition containing a perovskite-type composite oxide which exhibits a satisfactory catalytic performance over a long time even in a high temperature atmosphere and has a stable quality in which Rh and/or Pt dissolves to form a solid solution at a high rate. To achieve the object described above, in the present invention the catalyst composition is prepared to comprise an Rh-containing perovskite-type composite oxide represented by the following general formula (I) and/or a Pt-containing perovskite-type composite oxide represented by the following general formula (II) and a thermostable oxide optionally containing a noble metal.

Abstract: An object of the present invention is to provide an exhaust gas-purifying catalyst that is less prone to cause a decrease in its activity even when used at high temperatures in an atmosphere whose oxygen concentration is high. An exhaust gas-purifying catalyst of the present invention includes a composite oxide of alkaline-earth metal and aluminum, and platinum, wherein at least a part of the composite oxide and at least a part of the platinum forms a solid solution.

Abstract: An exhaust gas-purifying catalyst (1) contains a rare-earth element, an alkaline-earth element, zirconium and a precious metal, an atomic ratio of the alkaline-earth element with respect to the sum of the rare-earth element and the zirconium is equal to 0.1 atomic % or higher and lower than 10 atomic %, a part of the rare-earth element, a part of the zirconium and at least a part of the alkaline-earth element forming a composite oxide, and the composite oxide and a part of precious metal forming a solid solution.

Abstract: An object of the present invention is to provide an exhaust gas-purifying catalyst containing a composite oxide catalyst and a refractory support and being less prone to cause a decrease in its activity even when used at high temperatures in an atmosphere with high oxygen concentration. An exhaust gas-purifying catalyst includes a composite oxide catalyst containing rare-earth element, alkaline-earth element and precious metal, a part of the rare-earth element and a part of the alkaline-earth element forming composite oxide, and the composite oxide and a part of the precious metal forming solid solution, and a refractory support supporting the composite oxide catalyst and including at least one of a first composite oxide represented by a general formula AB2O4, a second composite oxide having perovskite structure represented by a general formula LMO3, and a third composite oxide having pyrochlore structure represented by a general formula X2Y2O7.

Abstract: To provide a heat-resistant oxide which is excellent in heat resistance and durability at high temperature and has high activity, a heat-resistant oxide which has an oxide crystal structure and in which a rate of a solid solution of a noble metal in the oxide crystal structure is 50% or more is obtained by heat-treating (secondarily baking) a precursor composition comprising zirconia, at least one coordinative element selected from the group consisting of rare earth elements, alkaline earth elements, aluminum and silicon, and at least one noble metal selected from the group consisting of platinum, rhodium and palladium at 650° C. or higher.

Abstract: An exhaust gas-purifying catalyst includes a carrier, and an active component formed of a noble metal, carried by the carrier. The carrier has a core portion comprising a cubic or tetragonal stabilized zirconia-based composite oxide containing at least one stabilizing element, and a surface layer portion including a heat resistant zirconia-based composite oxide formed on a surface of the core portion. The surface layer has a specific surface area which is larger than a specific surface area of the core portion. A part of the noble metal is solid-solutioned into the zirconia-based composite oxide of the surface layer portion, and the balance of the noble metal is carried on a surface of the surface layer portion.

Abstract: To provide a perovskite-type composite oxide which has stable quality in which a solid solution of Pd is formed at a high rate, a method for producing the perovskite-type composite oxide, and a catalyst composition containing the perovskite-type composite oxide, the perovskite-type composite oxide is produced by formulating materials in accordance with each atomic ratio of a perovskite-type composite oxide represented by the following general formula (1): AxB(1-y)PdyO3+???(1) wherein A represents at least one element selected from rare earth elements and alkaline earth metals; B represents at least one element selected from transition elements (excluding rare earth elements, and Pd), Al and Si; x represents an atomic ratio satisfying the following condition: 1<x; y represents an atomic ratio satisfying the following condition: 0<y?0.5; and ? represents an oxygen excess.

Abstract: An exhaust gas-purifying catalyst includes a carrier, and an active component formed of a noble metal, carried by the carrier. The carrier has a core portion comprising a cubic or tetragonal stabilized zirconia-based composite oxide containing at least one stabilizing element, and a surface layer portion including a heat resistant zirconia-based composite oxide formed on a surface of the core portion. The surface layer has a specific surface area which is larger than a specific surface area of the core portion. A part of the noble metal is solid-solutioned into the zirconia-based composite oxide of the surface layer portion, and the balance of the noble metal is carried on a surface of the surface layer portion.

Abstract: An exhaust gas-purifying catalyst includes a rare-earth element, an alkaline-earth element, and a precious metal. A part of the rare-earth element and a part of the alkaline-earth element form a composite oxide. The composite oxide and a part of the precious metal form a solid solution.

Abstract: An exhaust gas-purifying catalyst includes a support and a catalyst active component including at least one noble metal supported by at least a portion of the support. The support includes a stabilized zirconia containing at least one stabilizing element selected from rare earth elements and alkaline earth elements. 20 to 80% by weight of a total amount of the active component is supported in the support in a form of solid solution with the stabilized zirconia, and 80 to 20% by weight of a total amount of the active component is supported on a surface of at least a portion of the support.

Abstract: A catalyst for purifying an exhaust gas includes zirconia particles, and a transition metal layer, covering at least a part of a surface of the zirconia particles in a lamellar manner. It can reduce the emission of particulate materials (i.e., P.M.), such as SOF and sulfates, because the contacting area enlarges between the transition metal layer and materials to be purified.

Abstract: The present invention is a method of solidifying sulfur component being the cause of “SOx poisoning” by use of a sulfur solidifier. The solidifier includes a metal element having a function of oxidizing the sulfur component and a basic metal element. And the solidifier solidifies sulfur component before exhaust gas flows into an NOx-occluding reduction-type exhaust purifying catalyst located on an exhaust path. Since the foregoing sulfur solidifier includes the above metal element and the basic metal element, it can effectively solidify the sulfur component which are the cause of the SOx poisoning, and ensure improvement in purification performance.

Abstract: A catalyst for purifying an exhaust gas includes a support including rutile titania, an NOx storage material including at least on element selected from alkali metals, alkaline-earth metals and rare-earth elements and loaded on the support, and a noble metal loaded on the support. Since the rutile TiO2 and the NOx storage material form a fine composite oxide, the NOx storage material is likely to decompose even when it is subject to the sulfur poisoning, and the NOx storage material easily recovers the NOx storage ability. Therefore, the NOx storage material can be inhibited from the sulfur poisoning, and a high NOx conversion ratio can be maintained even after the service at an elevated temperature.

Abstract: A catalyst for purifying an exhaust gas includes zirconia particles, and a transition metal layer, covering at least a part of a surface of the zirconia particles in a lamellar manner. It can reduce the emission of particulate materials (i.e., P.M.), such as SOF and sulfates, because the contacting area enlarges between the transition metal layer and materials to be purified.

Abstract: The present invention is a method of solidifying sulfur component being the cause of “SOx poisoning” by use of a sulfur solidifier. The solidifier includes a metal element having a function of oxidizing the sulfur component and a basic metal element. And the solidifier solidifies sulfur component before exhaust gas flows into an NOx-occluding reduction-type exhaust purifying catalyst located on an exhaust path. Since the foregoing sulfur solidifier includes the above metal element and the basic metal element, it can effectively solidify the sulfur component which are the cause of the SOx poisoning, and ensure improvement in purification performance.

Abstract: 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.