Response of Metal Sites toward Water Effects on Postcombustion CO2 Capture in Metal–Organic Frameworks

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• 作者：Jiamei Yu ; Yufeng Wu ; Perla B. Balbuena
• 刊名：ACS Sustainable Chemistry & Engineering
• 出版年：2016
• 出版时间：April 4, 2016
• 年：2016
• 卷：4
• 期：4
• 页码：2387-2394
• 全文大小：629K
• ISSN：2168-0485

文摘

Coordinatively unsaturated metal (CUM) sites of metal–organic frameworks (MOFs) play an important role in water adsorption and its effects on CO₂ capture. To explore the trends among various metal identities toward water, M-HKUST-1 analogous to HKUST-1 based on different metal sites M (M = Zn, Co, Ni, and Mg) are chosen as model frameworks and their water effects on CO₂ capture are evaluated. Our results demonstrate that Mg-based framework shows diverse effects by water coordination from Zn-, Co-, and Ni-based frameworks. Water coordination lowers CO₂ uptake dramatically in Mg-HKUST-1 whereas improves CO₂ adsorption in Zn-, Co-, and Ni-HKUST-1 at most of the pressure ranges we studied. The detailed evaluation of interaction energy indicates that with the increased loading of CO₂ molecules both the weaker interactions between CO₂ and the framework and CO₂–CO₂ contribute to the lower CO₂ uptakes of the hydrated Mg-HKUST-1. These findings could benefit CUMs screening in MOFs’ design for CO₂ capture and other applications.