Ligand-Assisted Enhancement of CO2 Capture in Metal-Organic Frameworks
Ligand-Assisted Enhancement of CO2 Capture in Metal-Organic Frameworks
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DOI：
10.1021/ja2118943
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发表时间：
2012-04-18
影响因子：
15
通讯作者：
Neaton, Jeffrey B.
中科院分区：
文献类型：
--
作者：
Poloni, Roberta;Smit, Berend;Neaton, Jeffrey B.
利用含范德华校正泛函的密度泛函理论，我们阐明了二氧化碳如何与一种具有开放金属中心的新型“BTT型”金属 - 有机框架（MOF）结合。我们表明二氧化碳最有利地结合到开放金属阳离子位点，但吸附能对桥连配体选择的敏感度可能比对金属阳离子选择的敏感度高三倍。预测二氧化碳与开放金属位点之间存在强的三位点相互作用，结合能根据配体的不同最多可增强2倍。二氧化碳 - MOF的结合可归因于静电作用和范德华色散相互作用的组合，这两种作用对局部环境都极为敏感，并且对整体结合强度的贡献几乎相同。我们表明，明智地选择有机连接体和金属中心可使结合能从34.8 kJ/mol（对于CaBTTri）调节到最大值64.5 kJ/mol（MgBTT）。
Using density functional theory with a van der Waals-corrected functional, we elucidate how CO2 binds to a novel "BTT-type" metal-organic framework (MOF) featuring open metal centers. We show that CO2 binds most favorably to open metal cation sites, but with an adsorption energy that can be three times more sensitive to the choice of the bridging ligand than to metal cation choice. A strong, three-site interaction between CO2 and the open-metal site is predicted, with the binding energy enhanced by up to a factor of 2, depending on the ligand. The CO2-MOF binding can be attributed to a combination of electrostatics and vdW dispersive interactions, both of which are critically sensitive to the local environment, and both of which contribute nearly equally to the overall binding strength. We show that a judicious choice of the organic linker and the metal center allows the binding energy to be tuned from 34.8 kJ/mol (for CaBTTri) to a maximum of 64.5 kJ/mol (MgBTT).