| 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): n n A x B (1-y) Pd y O 3+δ (1) n nwherein 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 δ represents an oxygen excess. |