以溶胶-凝胶-超临界流体干燥法制备了CeO2-TiO2混合氧化物( n(Ce)/ n(Ti)=0.05～0.40),以其为载体,通过等体积浸渍法制备了Pd/CeO2-TiO2催化剂.XRD分析结果表明,在低Ce/Ti比的CeO2-TiO2混合氧化物中,CeO2高度分散于TiO2上;Ce/Ti比高于0.10时,大晶粒锐钛矿相TiO2和TiO2-CeO2固溶体或其前驱体无定形相共存.采用H2-TPR对所合成材料的氧化还原性能进行了研究.H2-TPR谱中500 ℃附近的耗氢峰对应于CeO2-TiO2中CeO2的还原,还原过程中不存在表面晶格氧与体相晶格氧的差别.由于TiO2与CeO2的协同作用,混合氧化物中形成了丰富的结构缺陷,提高了CeO2的氧化还原性能,其中Ce/Ti比为0.20时TiO2与CeO2的协同作用最显著.负载上Pd后,载体中CeO2的还原温度(＜150 ℃)大大降低,同时随着Ce/Ti比的增大,PdO与载体间的相互作用增强,导致PdO难于还原,相应的H2-TPR还原峰向高温方向移动.
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