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化学学报
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化学学报 ›› 2010, Vol. 68 ›› Issue (9): 851-857. 上一篇    下一篇

研究论文

CuCl与SiO2-TiO2载体相互作用的密度泛函理论研究

章日光，任军*，凌丽霞，刘树森，李忠   

  1. (太原理工大学煤科学与技术教育部和山西省重点实验室 太原 030024)
  • 投稿日期:2009-08-27 修回日期:2009-11-28 发布日期:2010-01-08
  • 通讯作者: 任军 E-mail:renjun@tyut.edu.cn
  • 基金资助:

    国家自然科学基金（批准号: 20606022和20776093）、国家重点基础研究发展规划（973计划）（2005CB221204）

A Density Functional Theory Study of Interaction of CuCl with Silica-titania Supports

Zhang Riguang Ren Jun* Ling Lixia Liu Shusen Li Zhong   

  1. (Key Laboratory of Coal Science and Technology, Ministry of Education and Shanxi Province, Taiyuan University of Technolgy, Taiyuan 030024)
  • Received:2009-08-27 Revised:2009-11-28 Published:2010-01-08

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以SiO<sub>2</sub>簇模型为基体, 通过Ti原子取代建立Ti中心原子上连接0个或1个OH基团的典型SiO<sub>2</sub>-TiO<sub>2</sub>复合氧化物模型来模拟处于体相中和表面上的四配位Ti(IV)中心. 采用广义梯度近似的密度泛函理论(DFT-GGA)研究了CuCl与SiO<sub>2</sub>-TiO<sub>2</sub>载体的相互作用. 计算结果表明, 在SiO<sub>2</sub>基体中嵌入Ti(IV)离子可以大大加强CuCl与氧化物载体之间的相互作用, 使CuCl/SiO<sub>2</sub>-TiO<sub>2</sub>催化剂的结构更稳定. 分子前线轨道表明Cu(I)作为催化剂的活性中心贡献了HOMO轨道, 容易失去电子; Ti(IV)中心原子贡献LUMO轨道, 容易得到电子, 计算结果与实验事实相一致.

关键词: 氯化亚铜, 二氧化硅, 钛硅复合氧化物, 几何构型, 密度泛函理论

The clusters contain 0 and 1 hydroxyl groups at the titanium center, noted as Ti<sub>bulk</sub>Si<sub>4</sub>Si<sub>6</sub> and Ti<sub>suf</sub>(OH)Si<sub>3</sub>Si<sub>6</sub>, respectively, were used to simulate the Ti(IV) center in the silica matrix. The interactions of CuCl with SiO<sub>2</sub>-TiO<sub>2</sub> mixed oxide were systematically studied by the first-principle DFT-GGA calculations. The calculation results show that incorporation of Ti atoms into silica can enhance the interaction of CuCl with the oxide support, leading to more stable CuCl/SiO<sub>2</sub>-TiO<sub>2</sub> catalysts. In addition, the frontier molecular orbital shows that the HOMO orbits of the CuCl/Ti<sub>bulk</sub>Si<sub>4</sub>Si<sub>6 </sub>and CuCl/Ti<sub>suf</sub>(OH)Si<sub>3</sub>Si<sub>6</sub> adsorbed clusters were mainly contributed by Cu atoms, while the LUMO orbits were contributed by Ti atoms. The calculation results were in accordance with the experimental facts.

Key words: cuprous chloride, silica, titanium-silica mixed oxide, geometric structure, density functional theory