物理化学学报 >> 2008, Vol. 24 >> Issue (04): 601-606.doi: 10.1016/S1872-1508(08)60026-1

研究论文 上一篇    下一篇

水滑石限域空间中Cl-与H2O的超分子作用

胥倩; 倪哲明; 潘国祥; 陈丽涛; 刘婷   

  1. 浙江工业大学化学工程与材料学院, 先进催化材料实验室, 杭州 310032
  • 收稿日期:2007-10-26 修回日期:2007-12-03 发布日期:2008-04-07
  • 通讯作者: 倪哲明 E-mail:jchx@zjut.edu.cn

Super-Molecular Interaction between Cl- and H2O within the Restricted Space of Layered Double Hydroxides

XU Qian; NI Zhe-Ming; PAN Guo-Xiang; CHEN Li-Tao; LIU Ting   

  1. Laboratory of Advanced Catalytic Materials, College of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310032, P. R. China
  • Received:2007-10-26 Revised:2007-12-03 Published:2008-04-07
  • Contact: NI Zhe-Ming E-mail:jchx@zjut.edu.cn

摘要: 构建水滑石(LDHs-Cl-yH2O)周期性计算模型, 选用密度泛函理论-赝势平面波法对模型进行几何全优化, 从结构参数、Mulliken电荷布居、态密度(DOS)、能量等角度研究层间Cl-和水分子的分布形态以及与LDHs层板间的超分子作用. 计算结果表明, LDHs-Cl主客体间存在着较强的超分子作用, 主要包括静电和氢键作用. LDHs-Cl层间引入水分子后, 随着水分子数的增加, 层间距逐渐增大后趋于平衡. 水合过程中氢键作用比静电作用更占优势, layer-water型氢键要略强于anoin-water型氢键. 当y=1, 2时, Cl-与水分子所在平面以平行层板的方式存在于LDHs层板间, 并且与两层板的距离基本相等; 当y=3, 4时, Cl-与水分子则以偏向某一层的方式随机地存在于LDHs 层板间. 随着层间水分子增加, LDHs-Cl-yH2O由离子型晶体向分子型晶体转化, LDHs-Cl的水合具有饱和量.

关键词: 水滑石, 超分子作用, 水合能, 密度泛函理论

Abstract: A periodical interaction model of LDHs-Cl-yH2O has been proposed. The geometry optimization and energy of the layered double hydroxides (LDHs) were calculated using CASTEP/LDAmethod at the CA-PZ level. The distribution of H2O in the interlayer and the super-molecular interaction between host layer and guest anion have been investigated by analyzing the geometric parameters, charge population, energy, and density of state (DOS ). The results showed that there was a strong super-molecular interaction between the host layer and the guest anion Cl -. In the system of LDHs-Cl-yH2O, the interlayer distance increased gradually then tended to invariableness. And in the process of hydration of LDHs-Cl, hydrogen bonding was superior to electrostatic interaction, and layer-water type hydrogen bonding was a little stronger than anion-water type hydrogen bonding between H2O and the rest of the structure. When y was 1 or 2, Cl- and the plane of water molecule were parallel to the layer; while y was 3 or 4 , distribution of Cl- and water was random. Moreover, the LDHs-Cl-yH2O would change from ionic crystal to molecular crystal with the increase of number of water molecule. The hydration of LDHs-Cl would achieve a definite saturation state.

Key words: Layered double hydroxides (LDHs), Super-molecular interaction, Hydration energy, Density function theory

MSC2000: 

  • O641