| 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. nA 1 x A 2 w B 1 1-(y+z) B 2 y Rh z O 3±´ (I) nA 3 r A 4 s B 3 1-(t+u) B 4 t Pt u O 3±´' (II) |