Exhaust gas purification catalyst and method for producing the same

A method for producing an exhaust gas purification catalyst in which a Rh-containing catalyst layer is located on a base material, the method comprising:

• providing a Pd-containing catalyst layer on a surface of the base material;
• preparing Rh-supporting Zr-based composite oxide in which Rh is supported on Zr-based composite oxide containing Zr and a rare earth metal except Ce, Rh-supporting CeZr-based composite oxide in which Rh is supported on CeZr-based composite oxide containing Zr and Ce, and Rh-doped CeZr-based composite oxide obtained by dissolving Rh in CeZr-based composite oxide serving as a binder material;
• performing a heat treatment on the Rh-supporting Zr-based composite oxide at a temperature of 550° C. to 800° C., both inclusive, in a reduction atmosphere containing CO;
• mixing the Rh-supporting Zr-based composite oxide subjected to the heat treatment, the Rh-supporting CeZr-based composite oxide, and the Rh-doped CeZr-based composite oxide together to produce a mixture, and making the mixture into slurry, thereby preparing a Rh-containing catalytic material;
• and
• providing the Rh-containing catalytic material on a surface of the Pd-containing catalyst layer.