CATALYST COMPOSITION

摘要

A catalyst composition, which comprises a perovskite-type composite oxide represented by the general formula (1): A1-xA'xB1-(y+z)B'yNzO3 (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 at least one element selected from Ti, Zr and Hf, B' represents at least one element selected from transition elements (exclusive of rare earth elements, Ti, Zr, Hf, Rh and Pt) and Al, N represents at least one element of Rh and/or Pt, x represents an atomic ratio in the numerical value range of 0 <= x <= 0.4, y represents an atomic ratio in the numerical value range of 0 <= y < 0.5, and z represents an atomic ratio in the numerical value range of 0 < z <= 0.5, with the proviso that x represents 0 when N represents only Pt]. The above catalyst composition allows the prevention of the decrease of its activity owing to the particle growth of Rh or Pt, and thus can exhibit excellent catalytic performance capabilities for a long period of time.