Sokhanvaran Vahid, Yeganegi Saeid
Department of Physical Chemistry, Faculty of Chemistry, University of Mazandaran, Babolsar, Iran.
Chemphyschem. 2016 Dec 15;17(24):4124-4133. doi: 10.1002/cphc.201601004. Epub 2016 Nov 3.
The quantum mechanics (QM) method and grand canonical Monte Carlo (GCMC) simulations are used to study the effect of lithium cation doping on the adsorption and separation of CO , CH , and H on a twofold interwoven metal-organic framework (MOF), Zn (NDC) (diPyNI) (NDC=2,6-naphthalenedicarboxylate; diPyNI=N,N'-di-(4-pyridyl)-1,4,5,8-naphthalenetetracarboxydiimide). Second-order Moller-Plesset (MP2) calculations on the (Li -diPyNI) cluster model show that the energetically most favorable lithium binding site is above the pyridine ring side at a distance of 1.817 Å from the oxygen atom. The results reveal that the adsorption capacity of Zn (NDC) (diPyNI) for carbon dioxide is higher than those of hydrogen and methane at room temperature. Furthermore, GCMC simulations on the structures obtained from QM calculations predict that the Li -doped MOF has higher adsorption capacities than the nondoped MOF, especially at low pressures. In addition, the probability density distribution plots reveal that CO , CH , and H molecules accumulate close to the Li cation site. The selectivity results indicate that CO /H selectivity values in Zn (NDC) (diPyNI) are higher than those of CO /CH . The selectivity of CO over CH on Li -doped Zn (NDC) (diPyNI) is improved relative to the nondoped MOF.
采用量子力学（QM）方法和巨正则蒙特卡罗（GCMC）模拟，研究了锂阳离子掺杂对一种双交织金属有机框架（MOF），即Zn（NDC）（diPyNI）（NDC = 2,6 - 萘二甲酸；diPyNI = N,N'-二（4 - 吡啶基）-1,4,5,8 - 萘四羧酸二亚胺）对CO、CH和H吸附与分离的影响。对（Li - diPyNI）簇模型进行的二阶Moller - Plesset（MP2）计算表明，能量上最有利的锂结合位点位于吡啶环一侧上方，距氧原子距离为1.817 Å。结果表明，在室温下，Zn（NDC）（diPyNI）对二氧化碳的吸附能力高于氢气和甲烷。此外，对由QM计算得到的结构进行GCMC模拟预测，锂掺杂的MOF比未掺杂的MOF具有更高的吸附容量，尤其是在低压下。另外，概率密度分布图显示，CO、CH和H分子在锂阳离子位点附近聚集。选择性结果表明，Zn（NDC）（diPyNI）中CO/H的选择性值高于CO/CH的选择性值。相对于未掺杂的MOF，锂掺杂的Zn（NDC）（diPyNI）对CO相对于CH的选择性有所提高。
