催化学报 ›› 2015, Vol. 36 ›› Issue (11): 1900-1909.DOI: 10.1016/S1872-2067(15)60961-5

• 论文 • 上一篇    下一篇

钼催化剂结构对其催化气相丙烯环氧化反应选择性的影响

Martin Šusteka, Bla?ej Horvátha, Ivo Vávrab,c, Miroslav Gála, Edmund Dobro?kab, Milan Hroneca   

  1. a 斯洛伐克理工大学化学与食品技术学院, Radlinského 9, 812 37, 布拉迪斯拉发, 斯洛伐克;
    b 斯洛伐克科学院电气工程研究院, Dúbravská cesta 2, 841 04, 布拉迪斯拉发, 斯洛伐克;
    c VŠB -俄斯特拉发工业大学纳米技术中心, 17. listopadu 15, 俄斯特拉发, 70800, 捷克共和国
  • 收稿日期:2015-06-10 修回日期:2015-07-25 出版日期:2015-11-02 发布日期:2015-11-02
  • 通讯作者: Blažej Horváth. 电话: +421-2 593 25 655; 传真: +421-2 524 95 381; 电子信箱: blazej.horvath@stuba.sk

Effects of structures of molybdenum catalysts on selectivity in gas-phase propylene oxidation

Martin Šusteka, Bla?ej Horvátha, Ivo Vávrab,c, Miroslav Gála, Edmund Dobro?kab, Milan Hroneca
  

  1. a Faculty of Chemical and Food Technology, Slovak University of Technology, Radlinského 9, 812 37 Bratislava, Slovakia;
    b Institute of Electrical Engineering, Slovak Academy of Sciences, Dúbravská cesta 2, 841 04 Bratislava, Slovakia;
    c VŠB-Technical University of Ostrava, Nanotechnology Centre, 17. listopadu 15, Ostrava, 70800, Czech Republic
  • Received:2015-06-10 Revised:2015-07-25 Online:2015-11-02 Published:2015-11-02

摘要:

考察了Mo基催化剂上空气气相氧化丙烯反应. 从无机的和有机金属Mo前驱体出发, 采用浸渍法和物理气相沉积法(PVD)制备了不同类型的SiO2负载氧化钼和Mo-Bi复合氧化物催化剂. 透射电镜结果证实, 所制催化剂上环氧化反应活性与其纳米结构直接有关. 催化剂中出现部分或完全结晶的氧化钼相, 它们与载体SiO2的相互作用较弱, 使得反应生成环氧丙烷的选择性低于10%, 而锚合在SiO2上的非结晶的八配位Mo物种上的环氧丙烷选择性达55%以上, 此时丙烯转化率约为11%. 不同形貌氧化钼的电化学表征结果证实了结构缺陷的重要性. 另外, 还讨论了Bi对氧化钼催化环氧化活性的直接促进效应.

关键词: 环氧丙烷, 环氧化, 氧化钼, 光学特性, 电化学性质

Abstract:

Molybdenum-based catalysts for the gas-phase oxidation of propylene with air were investigated. Various types of silica-supported molybdenum oxide and molybdenum-bismuth mixed oxide catalysts were prepared from inorganic and organometallic molybdenum precursors using wet impregnation and physical vapor deposition methods. The epoxidation activities of the prepared catalysts showed direct correlations with their nanostructures, which were identified using transmission electron microscopy. The appearance of a partly or fully crystalline molybdenum oxide phase, which interacted poorly with the silica support, decreased the selectivity for propylene oxide formation to below 10%; non-crystalline octahedrally coordinated molybdenum species anchored on the support gave propylene oxide formations greater than 55%, with 11% propylene conversion. Electrochemical characterization of molybdenum oxides with various morphologies showed the importance of structural defects. Direct promotion by bismuth of the epoxidation reactivities over molybdenum oxides is disputed.

Key words: Propylene oxide, Epoxidation, Molybdenum oxide, Optical property, Electrochemical property