铈锆固溶体的合成及对SOF的催化氧化

Preparation of Cerium/Zirconium Solid Solution and Catalytic Activity for Oxidization of SOF

采用溶胶凝胶法、溶液燃烧法、共沉淀法和表面活性剂模板法制备了Ce0．6Zr0．4O2,进行了XRD,BET比表面积的表征,研究了对柴油车尾气中可溶有机成分的催化氧化性能。XRD结果表明,4种方法合成出来的样品均形成了固溶体。BET结果表明,虽然高温焙烧前共沉淀法样品的比表面积最大,但是经高温焙烧后,它同溶液燃烧法和表面活性剂模板法的样品一样,比表面积发生了很大程度的衰减;而溶液燃烧法样品虽然在高温焙烧前比表面积最小,在高温焙烧后比表面积几乎没有发生衰减,表现了优异的热稳定性。采用DTA／TG法模拟催化氧化SOF的结果表明,经900℃高温焙烧后的样品都表现出较好的催化活性,可以作为柴油车氧化催化剂的主要助剂。

A series of cerium/zirconium oxides were prepared by four methods including sol-gel, solution combustion, co-precipitation and surfactant-assisted approach. The textural properties were characterized by XRD and BET. The catalytic oxidation properties for the combustion of SOF were studied by DTA/TG method. The XRD results show that all of them are found to form cerium/zirconium solid solutions. The BET results show, before calcined, the samples prepared by co-precipitation have the largest surface area, after calcined, however, their surface area decays greatly such as the samples prepared by sol-gel and surfactant-assisted approach. While the samples prepared by solution combustion have little surface area decay, behaving greatly high thermal stability, although they have the least surface area before calcining. After studying catalytic oxidation properties by DTA/TG method, it is found that the all samples calcined at 900 ℃ behave catalytic oxidation properties. Therefore, they can be used as the promoter of diesel oxidation catalyst.