表面活性剂模板法制备CeO2／CuO催化剂用于富氢气氛中CO优先氧化

摘要

A series of CeO2/CuO catalysts were prepared by surfactant-template method and hc aracterized by high resolution transmission electron microscope ( HRTEM ) , X-ray diffraction ( XR D ) , temperature-programmed reduction ( H2-TPR) and N2 sorption; their catalytic performance for preferential oxidation of CO ( CO-PROX) in H2-rich stream was investigated.The results show that the 4 nm CeO2 particles 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.ht e CuO is tes fo r CO ceh misorption and the Ce O2 sites supplyni g oxygen vacancies;the coexistence of two-kind surface sites on the contact interface is capable of promoting the preferential oxidation of CO.%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（X RD）、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。