Steam effects over Pd/Ce0.67Zr0.33O2-Al2O3 three-way catalyst

Ceria-zirconia-alumina （CZA） solid solution was prepared by sol-gel method in the present study. 0.5 wt.% Pd supported on CZA was prepared by incipient wetness impregnation. The steam effects for CO and C3H8 oxidation, three-way catalytic activity and stoichiometric window property were studied. The light-off temperature of the CO oxidation reaction shifted to a lower temperature due to the water-gas shift （WGS） reactions. The oxidation of C3H8 was enhanced due to the steam reforming （SR） reactions. The steam promoted the C3H8 oxidation and NO reduction in three-way catalytic reaction. The amplitude of stoichiometric window was amplified by the addition of water to the feed stream.