表面活性剂模板法制备CeO_2/CuO催化剂用于富氢气氛中CO优先氧化

CeO_2/CuO catalysts prepared by surfactant-template method for preferential CO oxidation in H_2-rich stream

采用表面活性剂模板法合成了一组不同配比的CeO2/CuO催化剂,使用高分辨透射电子显微镜(HRTEM)、X射线粉末衍射(XRD)、N2吸附脱附和程序升温还原(H2-TPR)等测试手段对催化剂进行了表征,并对其在富氢气氛中CO优先氧化的催化性能进行了研究。结果表明,立方相萤石结构的氧化铈颗粒粒径在4 nm左右,它们聚集成小簇后分散在块状氧化铜的表面;从粒径分布来看所制备的催化剂是逆负载型催化剂。催化性能测试结果显示,CeO2/CuO催化剂中有两种类型吸附位的存在,即由CuO提供的化学吸附位和由氧化铈提供的氧空位,而界面处两种类型吸附位的共存促进了CO的优先氧化。

A series of CeO2/CuO catalysts were prepared by surfactant-template method and characterized by high resolution transmission electron microscope（HRTEM）, X-ray diffraction（XRD）, temperatureprogrammed reduction（H2-TPR） and N2sorption; their catalytic performance for preferential oxidation of CO（CO-PROX） in H2-rich stream was investigated. The results showthat the 4 nm CeO2particles with cubic fluorite structure are agglomerated into small clusters and dispersed on the bulk CuO; CeO2/CuO may belong to a type of reverse supported catalyst on the basis of particle size distribution. There are two kinds of active sites in the CeO2/CuO system,i.e. the CuO sites for CO chemisorption and the CeO2sites supplying oxygen vacancies; the coexistence of two-kind surface sites on the contact interface is capable of promoting the preferential oxidation of CO.