摘要:
To provide an exhaust gas purifying catalyst which can maintain the catalytic activity at a high level over a long time and can achieve satisfactory emission control performance, an exhaust gas purifying catalyst is prepared so as to contain a noble metal, a perovskite-type composite oxide represented by the following general formula (3), and theta-alumina and/or alpha-alumina: AB1-mNmO3 (3) wherein A represents at least one element selected from rare-earth elements and alkaline earth metals; B represents at least one element selected from Al and transition elements excluding rare-earth elements and noble metals; N represents a noble metal; and m represents an atomic ratio of N satisfying the following relation: 0
摘要:
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. A1xA2wB11−(y+z)B2yRhzO3±δ (I) A3rA4sB31−(t+u)B4tPtuO3±δ′ (II)
摘要:
To provide a method for industrially efficiently producing an exhaust gas purifying catalyst containing a perovskite-type composite oxide which is stable and has a less reduced specific surface area and is also effectively prevented from decreasing in its catalytic performance even in endurance in high temperature oxidative reducing atmospheres, a pre-crystallization composition containing elementary components constituting a perovskite-type composite oxide containing a noble metal is prepared, is mixed with a powder of theta-alumina and/or alpha-alumina to prepare a mixture, and the mixture is heat treated. Thus, the resulting perovskite-type composite oxide supported by the powder of theta-alumina and/or alpha-alumina can keep its thermostability at a sufficient level thereby to effectively prevent the catalytic performance from decreasing. This method can industrially efficiently produce the exhaust gas purifying catalyst.
摘要:
To provide an exhaust gas purifying catalyst which can maintain the catalytic activity at a high level over a long time and can achieve satisfactory emission control performance, an exhaust gas purifying catalyst is prepared so as to contain a noble metal, a perovskite-type composite oxide represented by the following general formula (3), and theta-alumina and/or alpha-alumina: AB1−mNmO3 (3) wherein A represents at least one element selected from rare-earth elements and alkaline earth metals; B represents at least one element selected from Al and transition elements excluding rare-earth elements and noble metals; N represents a noble metal; and m represents an atomic ratio of N satisfying the following relation: 0
摘要:
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+δ (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
摘要:
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+δ (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
摘要:
To provide a method for industrially efficiently producing an exhaust gas purifying catalyst containing a perovskite-type composite oxide which is stable and has a less reduced specific surface area and is also effectively prevented from decreasing in its catalytic performance even in endurance in high temperature oxidative reducing atmospheres, a pre-crystallization composition containing elementary components constituting a perovskite-type composite oxide containing a noble metal is prepared, is mixed with a powder of theta-alumina and/or alpha-alumina to prepare a mixture, and the mixture is heat treated. Thus, the resulting perovskite-type composite oxide supported by the powder of theta-alumina and/or alpha-alumina can keep its thermostability at a sufficient level thereby to effectively prevent the catalytic performance from decreasing. This method can industrially efficiently produce the exhaust gas purifying catalyst.
摘要:
To provide an exhaust gas purifying catalyst which can maintain the catalytic activity of Pt at a high level over a long time and can achieve satisfactory emission control performance, an exhaust gas purifying catalyst is prepared so as to contain a composite oxide having a perovskite structure represented by the general formula (1): A1-xA′xB1-y-zB′yPtzO3 (1)wherein A represents at least one element selected from rare-earth elements and essentially including one or more rare-earth elements each having a valence of 3 as the only valence; A′ represents at least one element selected from alkaline earth metals and Ag; B represents at least one element selected from Fe, Mn, and Al; B′ represents at least one element selected from transition elements excluding Pt, Fe, Mn, Co, and the rare-earth elements; and x, y, and z are atomic ratios satisfying the following relations: 0
摘要翻译:为了提供能够长时间维持Pt的高水平的催化剂活性且能够达到令人满意的排放控制性能的排气净化催化剂,制备排气净化催化剂,以含有具有代表性的钙钛矿结构的复合氧化物 通过通式(1):<?in-line-formula description =“In-line Formulas”end =“lead”?> A <1> SUB> β1-yz B'> z O O O O O <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< description =“In-line Formulas”end =“tail”?>其中A表示选自稀土元素中的至少一种元素,并且基本上包括一种或多种每种价数为3的稀土元素作为唯一的价数; A'表示选自碱土金属和Ag中的至少一种元素; B表示选自Fe,Mn和Al中的至少一种元素; B'表示选自Pt,Fe,Mn,Co和稀土元素以外的过渡元素中的至少一种元素; x,y和z是满足以下关系的原子比:0