物理化学学报 >> 2001, Vol. 17 >> Issue (02): 111-115.doi: 10.3866/PKU.WHXB20010204

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Mn-Na2WO4/SiO2催化剂表面活性中心结构的DFT研究

陈宏善;牛建中;张兵;李树本   

  1. 西北师范大学物理系,兰州　730070；中科院兰州化学物理研究所,羰基合成与选择氧化国家重点实验室,兰州　730000
  • 收稿日期:2000-05-09 修回日期:2000-07-21 发布日期:2001-02-15
  • 通讯作者: 陈宏善 E-mail:chenhs@nwnu.edu.cn

DFT Study on the Active Sites in Mn-Na2WO4/SiO2 Catalyst

Chen Hong-Shan;Niu Jian-Zhong;Zhang Bing;Li Shu-Ben   

  1. Department of Physics ,Northwest Normal University,Lanzhou　730070; State Key Laboratory for Oxo Synthesis and Selective Oxidation,Lanzhou Institute of Chemical Physics,Lanzhou　730000
  • Received:2000-05-09 Revised:2000-07-21 Published:2001-02-15
  • Contact: Chen Hong-Shan E-mail:chenhs@nwnu.edu.cn

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摘要： 利用密度泛函方法(DFT)研究了MnNa2WO4/SiO2催化剂表面的活性中心结构.计算表明,在岐卜绞⒌ (111)面上,W能以单个或三个桥氧与载体作用形成稳定的四面体配位结构,Mn则能以单个桥氧与载体配位或形成不同结构的氧化物团簇；以单个桥氧担载的[WO4]四面体是最可能的甲烷活化中心.

关键词: Mn-Na2WO4/SiO2, 表面活性中心, DFT

Abstract: MnNa2WO4/SiO2 is one of the best catalysts for oxidative coupling of methane.To investigate the nature of active centers and the reaction mechanism,the structure of possible metal sites formed by tungsten and manganese over the silica surface were studied using molecular simulation method and ab initio DFT calculations.Silica support exists in the catalyst as 岐瞔ristobalite and its (111) face exposes preferentially to the surface.The calculated results show that tungsten interacts with the silica surface by three or one bridge oxygen atoms to form tetrahedral [WO4],and manganese interacts with single bridge oxygen to form dispersed [MnO4] or exists as oxide clusters.The nature of the molecular orbitals and the electronic structure suggest that the tetrahedral [WO4] site with single bridge oxygen is the most probable active center responsible for methane activation.

Key words: Mn-Na2WO4/SiO2, Active sites, DFT