The effect of synthesis method on the properties and catalytic performance of Pd/Ce0.5Zr0.5O2-Al2O3 three-way catalyst

Abstract

Three Ce0.5Zr0.5O2-Al2O3 compounds were prepared using conventional coprecipitation method, mechanical mixing technique and a novel modified coprecipitation route, afterwards the corresponding Pd-only three-way catalysts were obtained by wet-impregnation method. Differences in textural, structural, morphological, reduction properties and catalytic performance, together with the thermal aging behaviors of the catalysts were investigated systematically. The results revealed that different mixing strategies of Ce0.5Zr0.5O2(CZ) and Al2O3 led to different interaction between CZ and Al2O3, thus modified the textural, structural and reduction properties of the supported catalysts to different extents, and brought about various atom rearrangements during the aging process. The catalyst supported on Ce0.5Zr0.5O2-Al2O3 obtained by the modified coprecipitation method displayed the least distinction before and after aging treatment, and it presented superior textural, structural and reduction properties after aging, which consequently resulted in enhanced three-way catalytic performance, the light-off temperatures of C3H8, CO and NO were 327°C, 164°C and 208°C, respectively, obviously lower than those of the catalysts originated from the conventional coprecipitation method and mechanical mixing route.