Effect of Calcination Temperature on Three-Way Catalytic Performance of Pd/Ce0.65Zr0.35O2 Prepared by Soft-Hard Template Method

High thermal stability Ce0.65Zr0.35O2(CeZr) was prepared by soft -hard template method. The influence of calcination temperature on properties of Ce0.65Zr0.35O2 and its corresponding Pd based three-way catalyst (TWC) was investigated. The samples were analyzed by X-ray diffraction, surface area analysis, Raman spectrum, X-ray photoelectron spectroscopy, oxygen storage capacity and H-2 -temperature -programmed reduction. The results indicate that the structure and redox properties are strongly influenced by calcination temperature. The structure properties, for instance, BET (Brunaner-Emmett-Teller) surface area declined along with the rise of temperature, but the BET surface area of the sample calcinated at 1 000 degrees C was 61 m(2). g(-1), which was significantly higher than that calcinated direct in air at the same temperature. The OSC and reduction property of Ce0.65Zr0.35O2 increased with the rise of calcination temperature because of phase rearrangement at high temperature. The redox property of their corresponding catalysts decreased due to descending of Pd dispersion, which results in decline of three-way catalytic activity at last. Although high temperature sintering led to decrease of catalytic performance, the catalyst prepared by soft -hard template method calcinated at 1 000 degrees C still had excellent activity. The light -off temperature for C3H8, CO and NO was 274, 175 and 133 degrees C, respectively, which was significantly lower than catalyst calcined direct in air at the same temperature. Redox property and dispersity of Pd are significant factors affecting activity of catalyst.