Abstract Highly efficient separation of residual carbon dioxide (CO 2 ) from syngas, mainly composed of carbon monoxide (CO) and hydrogen (H 2 ), could not only make its utilization more energetically efficient but also avoid catalysts poisoning in some industrial applications. In the attempts to address this issue, it is acknowledged that CO 2 /CO separation is the vital step since H 2 is a nonpolar molecules, difficult to be polarized and could be easily separated from CO 2 . Herein, we report a novel strategy to graft basic ethylenediamine (ED) molecules onto porous metal–organic frameworks (MOFs) as solid adsorbents for CO 2 /CO separation via solvent ‘squeezing’ approach, in which Cu 3 (BTC) 2 (BTC = 1,3,5-benzenetricarboxylate) MOF was employed as the pristine MOF. Surprisingly, the ED-grafted Cu 3 (BTC) 2 shows unprecedented enhancement of CO 2 /CO selectivity of 226% at 273 K and 861% at 298 K, respectively, in comparison with the solvent-free Cu 3 (BTC) 2 . Moreover, despite the large isosteric heats of adsorption of CO 2 on the ED-grafted Cu 3 (BTC) 2 , it could be easily regenerated at moderate temperature. This work provides an efficient and facile method to functionalize MOFs for CO 2 capture.

中文翻译：

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在 Cu 3 (BTC) 2 上接枝乙二胺以实现高效 CO 2 /CO 分离的溶剂“挤压”策略

摘要 从主要由一氧化碳（CO）和氢气（H 2 ）组成的合成气中高效分离残余二氧化碳（CO 2 ），不仅可以提高其利用效率，而且可以避免某些工业应用中的催化剂中毒。在解决这个问题的尝试中，公认CO 2 /CO 分离是至关重要的步骤，因为H 2 是非极性分子，难以极化并且可以很容易地与CO 2 分离。在此，我们报告了一种通过溶剂“挤压”方法将碱性乙二胺 (ED) 分子接枝到多孔金属有机骨架 (MOF) 上作为固体吸附剂用于 CO 2 /CO 分离的新策略，其中 Cu 3 (BTC) 2 (BTC = 1,3,5-苯三羧酸酯）MOF 用作原始 MOF。出奇，与无溶剂的 Cu 3 (BTC) 2 相比，ED 接枝的 Cu 3 (BTC) 2 显示出前所未有的 CO 2 /CO 选择性在 273 K 和 298 K 时分别提高了 226% 和 861%。此外，尽管 CO 2 在 ED 接枝的 Cu 3 (BTC) 2 上的等量吸附热很大，但它可以很容易地在中等温度下再生。这项工作提供了一种有效且简便的方法来使 MOF 功能化以捕获 CO 2 。