“软-硬”模板法制备的Pd/Ce_(0.65)Zr_(0.35)O_2催化剂的结构和性能

The Structure and Performance of Pd/Ce_(0.65)Zr_(0.35)O_2 Catalysts Prepared by Soft-Hard Template Method

采用"软-硬"模板法合成了Ce_(0.65)Zr_(0.35)O_2(CZ),并以其为载体制备了单Pd催化剂。采用能谱分析(EDS),激光拉曼光谱(Laser Raman)对焙烧的中间产物及CZ进行了表征分析;对催化剂进行了粉末X射线衍射(XRD),X射线光电子能谱(XPS),N_2吸附-脱附,储氧量(OSC),CO脉冲吸附和H_2程序升温还原(H_2-TPR)的表征,并对其三效催化活性进行了测试。结果表明:"软-硬"模板法在提高Pd/CZ催化剂的比表面和孔容的同时提高了催化剂中Ce^(3+)的比例和Pd的分散性,改善了固溶体的均一性,从而显著提高了其氧化还原性能和催化性能,使催化剂在老化前后都表现出了优异的三效催化活性。老化后对C_3H_8、CO、NO的起燃温度分别为318、180、210℃,低于软模板法合成的Pd/CZ催化剂,表现出优异的热稳定性。

Ce0.65Zr0.35O2（CZ） was synthesized by soft-hard template method and its corresponding Pd only catalyst was also prepared. The intermediate product and CZ were characterized by energy dispersive spectrometer （EDS） and laser raman spectroscopy. The Pd/CZ catalyst was investigated by X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, N2-physical adsorption, oxygen storage capacity （OSC）, impulse CO chemisorption and H2-temperature programmed reduction （H2-TPR） technologies. It was found that soft-hard template method offered catalyst with high surface area and pore volume, enhanced the ratio of Ce^3 ＋, Pd dispersion and homogeneity of solid solution. It also imparted catalyst excellent three-way catalytic performance before and after aging. After aging, the light-off temperatures to C3Hs, CO and NO were 318, 180 and 210 ℃ respectively, which were lower than aged catalyst synthesised by soft template, behaved strong anti-sintering property.