溶胶-凝胶法制备钒掺杂中孔氧化硅及丙烷氧化脱氢的研究

V-meso-SiO_2 catalysts prepared by sol-gel methods and their application in the oxidative dehydrogenation of propane

采用溶胶-凝胶法制备了钒掺杂中孔氧化硅(V-meso-SiO2),用N2物理吸附、X射线衍射、透射电镜、拉曼光谱、紫外可见漫反射、红外光谱、程序升温脱附、程序升温还原系统研究了催化剂的物化性质并测试了其在丙烷氧化脱氢反应中的催化性能。结果表明:V-meso-SiO2催化剂具有约600 m2/g的比表面、5.0 nm左右的平均孔径、类似蠕虫状的介孔孔道结构;氧化钒在材料的骨架内主要是以高度分散的孤立态的四面体钒存在,是丙烷氧化脱氢反应的活性中心位;通过优化反应温度、原料气体流速等条件,V-meso-SiO2催化剂对于丙烷氧化脱氢反应具有较好的催化活性。

V-meso-SiO： catalysts have been prepared by a sol-gel method and characterized using N2 physisorption, X-ray diffraction （XRD）, transmission electron microscopy （TEM）, Raman spectroscopy, UV-Vis diffuse reflec- tance spectroscopy, infrared spectroscopy, temperature-programmed desorption （TPD） and temperature-pro- grammed reduction （TPR）. The BET surface area and pore size of the samples were around 600 m2/g and 5.0 nm, respectively. The structure of V-meso-SiO2 catalysts is similar to that of hexagonal mesoporous silica （HMS） with a worm-like arrangement. The vanadium species are highly dispersed and are mainly in a tetrahedral environment. Since these are the active sites for the oxidative dehydrogenation of propane, the catalytic performance of the cata- lysts was tested in this reaction and the catalytic performance of V-meso-SiO2 was optimized by varying the synthesis and reaction conditions.