MoO_3/SnO_2催化剂的酸位及氧化中心研究  

Research on acid sites and oxidation center in MoO_3/SnO_2 catalyst

作　　者：王吉清[1] 苏永超[2] 张继德[1] 许利剑[1] 张薇[3] 

机构地区：[1]湖南工业大学绿色包装与生物纳米技术应用实验室,湖南株洲412000 [2]中国科学院武汉物理与数学研究所,湖北武汉430071 [3]湖南农业大学理学院,湖南长沙410128

出　　处：《湖南农业大学学报（自然科学版）》2007年第2期247-252,共6页Journal of Hunan Agricultural University(Natural Sciences)

基　　金：国家科技部"十五"科技攻关项目(2005DA531)

摘　　要：采用固体核磁共振及密度泛涵理论计算方法研究了MoO3/SnO2催化剂的结构和性质及其固体酸性.结果表明:在这种催化剂中,钼组分主要是散布在氧化锡表面而非大幅度融入氧化锡晶格结构中;Brnsted酸位和Lewis酸位同时存在,酸性强于沸石分子筛(如HY和HZSM-5),但酸位浓度相对较低.理论方法计算的催化剂上吸附丙酮的13C化学位移与试验结果很接近,证实了所提出的Brnsted酸位结构为—Mo—(OH)—Sn—.固体核磁共振试验还证实了这种负载氧化物的氧化性,最后提出了Lewis酸位才是其氧化反应的活性中心.Research on the structure and properties, especially the solid acidity and catalytic nature, of molybdenum oxide supported on tin oxide, by use of solid-state nuclear magnetic resonance （SSNMR） spectroscopy and density functional theory （DFT） calculation, were performed. As demonstrated by solid-state NMR experiments, BrФnsted as well as Lewis acid sites are created in our MoO3/SnO2 sample. Overall acid is stronger than those of zeolites, e.g., HY and HZSM-5, in strength, though concentration of acid sites is relatively lower. The DFT computational ^13C chemical shift for acetone absorbed on MoO3/SnO2 is in well agreement with the experimental value, which confirms the local structure of --Mo--（OH）--Sn-- for BrФnsted acid site. Reducibility of this supported metal oxide is also demonstrated by solid-state NMR experiments and active oxidation center of this catalyst is proposed as well.

关 键 词：MoO3/SnO2催化剂 酸位 固体核磁共振 密度泛涵 氧化性 

分 类 号：O641[理学—物理化学]