The catalytic activity of Rh/CeO2 ZrO2 for NO CO C3H6-H-2-O-2 reactions under stoichiometric conditions was significantly improved by the addition of Jr. The optimum Ii/Rh atomic ratio was 1/9. The improvement was ascribed to the formation of finely divided Jr species on the surface of Rh particles. IrRh/CeO2-ZrO2 with an IrRh loading of 0.3 wt % showed high catalytic performance, which is comparable with that of 0.5 wt % Rh/CeO2-ZrO2, leading to minimize the Rh usage.