Improving Carbon Dioxide Storage Capacity of Metal Organic Frameworks by Lithium Alkoxide Functionalization: A Molecular Simulation Study

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• 作者：Jianbo Hu ; Jing Liu ; Yang Liu ; Xiao Yang
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：May 19, 2016
• 年：2016
• 卷：120
• 期：19
• 页码：10311-10319
• 全文大小：925K
• 年卷期：0
• ISSN：1932-7455

文摘

Metal organic frameworks (MOFs) represent a new kind of porous solid and have shown promising potential for carbon dioxide (CO₂) capture and separation. In this work, grand canonical Monte Carlo simulations were performed to explore lithium alkoxide functionalization for improving CO₂ adsorption capacity in HKUST-1, MOF-143, and MOF-399. The results show that lithium alkoxide functionalization remarkably improves the CO₂ uptake ability in all three kinds of MOFs at 298 K, especially at the low-pressure range. The CO₂ uptake amount in lithium-functionalized HKUST-1 increased more than 1700% compared with its unfunctionalized form at 1 kPa. Furthermore, the extension of organic linkers leads to lower CO₂ adsorption capacity at the low-pressure range due to the lower isosteric heat, but higher CO₂ adsorption capacity at the high-pressure range resulting from the increase of total free volume. Specifically, the incorporation of Li atoms onto the frameworks induced a shift of preferential adsorption sites for CO₂. The CO₂ molecules were first adsorbed around the Li atoms in the three lithium-functionalized MOFs.