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沸石咪唑脂骨架材料(ZIFs)是一种新型的温室气体CO_2吸附材料。本文采用密度泛函理论计算CO_2在ZIF-68两种不同类型链(nIM和bIM)上的吸附能,计算中选用GGA/PW91泛函。计算结果表明CO_2分子在nIM链上和bIM链上的吸附存在明显的差异。在bIM链上,由于弱的C-H键的存在导致吸附过程中链的几何形状容易发生变形,从而得到较大的吸附能。吸附过程中CO_2分子的键角均有变化,在硝基官能团附近发生吸附时由于硝基的极化作用导致CO_2分子键角变化较其它吸附位变化明显。CO_2分子在nIM和bIM链上的吸附主要以物理吸附为主,范德华力是主要的相互作用力。
Zeolite imidazole lipid matrix material (ZIFs) is a new type of greenhouse gas CO 2 adsorbent. In this paper, the adsorption energies of CO_2 on two different types of chains (nIM and bIM) of ZIF-68 were calculated by using density functional theory. The GGA / PW91 functional was selected for the calculation. The calculated results show that there is a significant difference in the adsorption of CO 2 between the nIM chain and the bIM chain. In the bIM chain, due to the presence of weak C-H bond leading to the adsorption process of the chain geometry easily deformed, resulting in a larger adsorption energy. The bond angles of CO 2 molecules changed during the adsorption process. The change of bonding angle of CO 2 molecules was more obvious than that of other adsorption sites due to the polarization of nitro groups when the adsorption occurred near the nitro functional groups. The adsorption of CO 2 molecules on nIM and bIM chains is mainly physical adsorption, and van der Waals forces are the main interaction forces.