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Tuning the hydrogen adsorption properties of Zn–based metal–organic frameworks: Combined DFT and GCMC simulations
Journal of Solid State Chemistry ( IF 3.2 ) Pub Date : 2018-04-26 , DOI: 10.1016/j.jssc.2018.04.033
Suye Yu , Shina Li , Xianhe Meng , Chubin Wan , Xin Ju

This study aims to guide the future design of metal-organic frameworks (MOFs) for hydrogen storage. At 77 K, azulenedicarboxylate (ADC)-substituted MOF-5 increases the hydrogen adsorption rate and hydrogen uptake capacity when the pressure exceeds 12 bar. At 297 K, ADC substitution significantly increases hydrogen adsorption when the pressure exceeds 5 bar. The grand-canonical Monte Carlo (GCMC) detailed analyses indicate that with increased pressure, hydrogen molecules in MOFs tend to be located at the corner region, organic linkers, and the center of cores. Meanwhile, high pressure adsorption shows that the large space due to ADC substitution leads to reduced steric effect around metal sites. Analysis of density of states illustrates that the introduced organic linkers may contribute sufficient electrons and enhance electron flow. These electrons can induce an electric field-effect, which increases the polarisation of hydrogen atoms and molecules surrounding linkers. Amongst the studied MOFs, substitution with Ni exerts no obvious effect on hydrogen storage.



中文翻译:

调整基于锌的金属-有机骨架的氢吸附特性:DFT和GCMC组合模拟

这项研究旨在指导未来用于储氢的金属有机框架(MOF)的设计在77 K下,当压力超过12 bar时,a二烯二羧酸酯(ADC)取代的MOF-5会增加氢吸附速率和氢吸收能力。在297 K时,当压力超过5 bar时,ADC取代会大大增加氢的吸附。宏伟规范蒙特卡洛详细的分析(GCMC)表明具有增加的压力,在MOFs材料氢分子趋向于位于角区域中,有机连接基,和芯的中心。同时,高压吸附表明,由于ADC置换而产生的较大空间导致金属位点周围的空间效应降低。分析态密度表明,引入的有机连接基可贡献足够的电子并增强电子流。这些电子可以感应电场效应,从而增加氢原子和接头周围分子的极化。在所研究的MOF中,Ni的取代对氢的存储没有明显的影响。

更新日期:2018-07-12
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