Catalyst for purifying an exhaust gas

摘要

A catalyst for purifying an exhaust gas includes a composite oxide including gold (Au) and having crystalline unit cells in every one of which an Au ion is disposed. Since the Au exists in a state of an ion, the catalyst exhibits a good catalytic activity. Since the Au is present in such a manner that it is surrounded by the other elements, it is inhibited from moving. As a result, the catalyst is improved in terms of the heat resistance.