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 分子催化  2019, Vol. 33 Issue (6): 551-560 0

### 引用本文

SUN Yi-fan, JIA Guang-xin, HE Bei-bei. DFT Investigation on the CO2 Adsorption of Confined Ionic Liquids[J]. Journal of Molecular Catalysis (China), 2019, 33(6): 551-560.

### 文章历史

DFT Investigation on the CO2 Adsorption of Confined Ionic Liquids
SUN Yi-fan , JIA Guang-xin , HE Bei-bei
College of Chemical Engineering and Technology, North University of China, Taiyuan 030051, China
Abstract: In recent years, the greenhouse effect has become increasingly serious, so CO2 absorbing materials have received widespread attention. In this work, we have performed the density functional theory (DFT) calculations to study the CO2 adsorption of confined ionic liquids within SiO2. Comparing the interaction of the ionic liquids (ILs) and the confined ionic liquids with CO2, the adsorption conditions of the two systems in these two states are quite different. Researches on ILs, SiO2 and ILs/SiO2 composite structures are carried out from the aspects of geometric structure, interaction and charge analysis. The calculation results show that there is a strong interaction between them. The loading of the ionic liquids not only changed the structure of the SiO2 support, but also the interaction forces between anions and cations. The calculation results lay a theoretical foundation for further in-depth adsorption of CO2 by the ionic liquids.
Key words: CO2    adsorption    confined ionic liquids    SiO2    density functional theory(DFT)

MCM-41作为性能良好的介孔氧化硅材料, 在药物传递[17-20]、气体分离与捕获[21]、催化[22-27]等方面有着广泛的应用研究.研究以MCM-41为载体的限域离子液体具有极大的意义.

 图 1 优化后的SiO2结构 Fig.1 Optimized structure of SiO2
1 计算方法

 $\Delta {\rm E} = {\rm E}\left( {{\rm A}{\rm B}} \right) - {\rm E}\left( {\rm A} \right) - {\rm E}\left( {\rm B} \right) + {\rm{ }}\Delta ZPVE$ (1)

ΔZPVE是零点振动能. E(AB)是复合材料的总能量. E(A)、E(B)分别是A和B在复合材料中的能量.

2 结果与讨论 2.1 CO2-ILs的结构优化以及能量变化

 图 2 离子液体的优化结构 Fig.2 Optimized structure of the ionic liquids

 图 3 CO2-ILs体系优化后的结构以及相互作用的最小距离(Å) Fig.3 The optimized structure of CO2-ILs system and the minimum distance of the interaction(Å)

2.2 CO2-ILs/SiO2的结构优化以及能量变化

 图 4 优化后的限域离子液体结构以及相互作用的最小值(Å) Fig.4 The optimized structure of confined ILs and the minimum distance of the interaction(Å)

2.3 电荷分布

 图 5 体系中参与作用的重要位置 Fig.5 Important participation in the System

3 结论