催化学报

催化学报 ›› 2009, Vol. 30 ›› Issue (1): 24-30.

• 研究论文 • 上一篇    下一篇

TS-1分子筛Lewis酸性的理论研究

王伊蕾,邢双英,曹亮,王善鹏,周丹红   

  1. 辽宁师范大学化学化工学院功能材料化学研究所, 辽宁大连 116029
  • 收稿日期:2009-01-25 出版日期:2009-01-25 发布日期:2012-10-17

Theoretical Study of the Lewis Acidity of TS-1 Zeolite

WANG Yilei, XING Shuangying, CAO Liang, WANG Shanpeng, ZHOU Danhong*   

  1. Institute of Chemistry for Functionalized Materials, College of Chemistry and Chemical Engineering, Liaoning Normal University, Dalian 116029, Liaoning, China
  • Received:2009-01-25 Online:2009-01-25 Published:2012-10-17

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1040

被引次数

43

摘要： 应用密度泛函理论和量子力学与分子力学联合的ONIOM2方法对含Ti的MFI分子筛(TS-1)中Ti4+离子在三种不同骨架落位上所表现的Lewis酸性进行了理论研究. 利用碱性探针分子(CO, NH3, 乙腈和吡啶)在骨架Ti活性中心的吸附作用,对吸附络合物的几何结构和吸附能进行了计算,并通过自然键轨道(NBO)分析考察了吸附络合物的电子结构. 结果表明,骨架Ti在T12位表现出明显的Lewis酸性,对NH3分子有较强的吸附作用. NBO分析表明,骨架Ti活性中心的Lewis酸性是由于Ti-O键的空σ反键轨道接受碱性探针分子提供的孤对电子; NH3分子吸附导致Ti4+离子由近正四面体中心对称变为五配位的三角双锥对称.

关键词: 钛硅分子筛, Lewis酸性, 吸附, 密度泛函理论, 自然键轨道分析

Abstract: The Lewis acidity of TS-1 zeolite was theoretically studied by calculating the adsorption energies of basic probe molecules on different Ti centers. The result s indicated that Ti located at the T12 site presents obvious Lewis acidity, whic h can strongly adsorb NH3 through providing the empty σ*(Ti- O) orbital to accept the lone pair electrons.

Key words: TS-1 zeolite, Lewis acidity, adsorption, density functional theory, natural bond orbital analysis