CATALYSTS

摘要

Catalysts wherein noble metals are efficiently supported on the surfacemost layers thereof. Catalysts obtained by forming a double oxide layer on a carrier in such a way that the layer can contain a perovskite-type double oxide represented by the general formula (1) and other double oxide and dipping the resulting carrier in an aqueous solution of a noble metal salt to incorporate the solution in the carrier and form a noble metal layer in a state supported on the surfacemost layer of the carrier: A<SUB>x</SUB>B<SUB>y</SUB>O<SUB>3±d</SUB> (1) wherein A is at least one element selected from among rare earth elements and alkaline earth metals; B is at least one element selected from among transition elements (except rare earth elements); x is an atomic fraction of less than 1; y is an atomic fraction of 1.0; and d is an excess or deficiency of oxygen.