介孔混合氧化物催化剂LA-CO-ZR-O的制备与表征  

Preparation and Characterization of Mesoporous Mixed Oxide Catalyst La-Co-Zr-O

作　　者：邹志强[1] 孟明[1] 查宇清[1] 谢亚宁[2] 胡天斗[2] 刘涛[2] 

机构地区：[1]天津大学化工学院催化科学与工程系,天津300072 [2]中国科学院高能物理研究所,北京100049

出　　处：《催化学报》2006年第2期129-134,共6页

基　　金：天津市自然科学基金(05YFJMJC09700);天津大学985教育振兴行动计划资助项目

摘　　要：采用柠檬酸络合-有机模板剂分解法制备了（La＋Co）／（La＋Co＋Zr）原子比为0．5的La-Co-Zr-O催化剂，并与传统的共沉淀法制备的La-Co-Zr-O催化剂进行比较，N2物理吸附结果表明，采用模板剂法制备的催化剂样品具有较大的比表面积（96．6～117．6m^2／g）和十分均匀的孔径（3．5～4．3nm）；X射线衍射、X射线光电子能谱和X射线吸收精细结构表征结果一致表明，催化剂中活性组分主要为高分散的Co3O4微晶（粒径为23～33nm），模板剂法制备的催化剂中所有组分的分散性均优于共沉淀法制备的催化剂．程序升温还原实验结果表明，采用聚乙二醇辛基苯基醚与十六烷基三甲基溴化铵为混合模板剂制备的催化剂中Co3O4更容易被还原,Co-O键的活动度与催化剂催化氧化反应的活性密切相关．The mixed/complex oxide catalysts prepared by the normal co-precipitation method possess low surface area, poor component dispersion, and wide pore size distribution. In this work, the method for the Si-Al zeolite synthesis was used for reference to prepare the La-Co-Zr-O （（La ＋ Co）/（La ＋ Co ＋ Zr） atomic ratio was 0.5） mixed oxide catalysts with large surface area and narrow pore size distribution. Cetyl trimethyl ammonium bromide （CTAB）, p-octyl polyethylene glycol phenyl ether （OP）, and their mixture were used as the templates, respectively. N2 adsorption, X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, extended X-ray absorption fine structure （EXAFS） spectroscopy, and temperature-programmed reduction （H2-TPR） were employed to characterize the catalysts. The N2 adsorption results show that the obtained samples possess large specific surface area （96.6-117.6 m^2/g） and uniform pore diameter （3.5-4.3 nm）. The results of XRD, XPS, and Co K-edge EXAFS indicate that the highly dispersed Co3O4 crystallite （23-33 nm） is the main active phase for CO oxidation. Compared with the catalyst prepared by co-precipitation method, the samples prepared by citric acid complexation-organic template decomposition method have much higher component dispersion and catalytic activity. The H2-TPR results reveal that the Co3O4 phase in the sample prepared using mixed templates of CTAB and OP is easier to be reduced, which is relevant to the catalyst activity for CO oxidation.

关 键 词：介孔材料 氧化镧 氧化钴 氧化锆 一氧化碳 催化氧化 十六烷基三甲基溴化铵 聚乙二醇辛基苯基醚 

分 类 号：O643.36[理学—物理化学]