不同铈和锆前体对铈锆固溶体性能的影响

Influence of Ce and Zr precursors on the properties of Ce-Zr solid solution

分别以CeO2和Ce(NO3)3铈前体,ZrOCl2和ZrO(NO3)3为锆前体,采用通常的共沉淀法和以双氧水为氧化剂的氧化还原共沉淀法制备Ce0.5Zr0.5O2固溶体。通过XRD、N2-BET和H2-TPR等手段表征了铈锆固溶体结构及其物理化学性质;同时以CO氧化和CH4催化燃烧作为探针反应考察其催化性能。结果表明,以不同铈前体和锆前体合成的铈锆复合氧化物均形成了具有二氧化铈立方萤石型晶相的固溶体。但是对以相同铈前体制备的铈锆固溶体,以ZrO(NO3)3为锆前体制备的催化剂比以ZrOCl2为锆前体制备的样品比表面积更大;以相同锆前体制备的铈锆固溶体,以含四价铈的盐为前体制备的样品储氧量更大,但采用含三价铈的盐氧化还原共沉淀制备的样品比表面积则更大。

The Ce0.5 Zr0.5 O2 solid solutions were prepared by co-precipitation and redox--coprecipitation methods, using CeO2 or Ce（NO3）3 as cerium precursor and ZrOCl2 or ZrO（NO3）3 as zirconium precursor, The physical and chemical properties of all the samples were tested by N2-BET, H2- TPR and XRD, The catalytic reaction performance of the catalysts was investigated by using CH4 and CO oxidation as prohing reactions. XRD results demonstrated that Ce--Zr solid solution phase with cubic fluorite structure was formed in all of the samples. With the same cerium precursor, the Ce--Zr solid solution samples prepared with ZrO（NO3）3 had higher specific surface areas than the samples prepared with ZrOCl2. With the same zirconium precursor,the Ce-Zr solid solution samples prepared with Ce^4＋ precursor had a larger oxygen storage amount, while the Ce-Zr solid solution samples prepared with Ce^3＋ precursor by redox--coprecipition method had higher specific surface areas.