Department of Chemical and Biomolecular Engineering, National University of Singapore, 117585, Singapore, Singapore.
Department of Chemistry, The University of Manchester, Manchester, M13 9PL, UK.
Nat Commun. 2023 Jun 24;14(1):3789. doi: 10.1038/s41467-023-39319-2.
The interactions between adsorbed gas molecules within porous metal-organic frameworks are crucial to gas selectivity but remain poorly explored. Here, we report the modulation of packing geometries of CO and CH clusters within the ultramicroporous CUK-1 material as a function of temperature. In-situ synchrotron X-ray diffraction reveals a unique temperature-dependent reversal of CO and CH adsorption affinities on CUK-1, which is validated by gas sorption and dynamic breakthrough experiments, affording high-purity CH (99.95%) from the equimolar mixture of CH/CO via a one-step purification process. At low temperatures (<253 K), CUK-1 preferentially adsorbs CO with both high selectivity (>10) and capacity (170 cm g) owing to the formation of CO tetramers that simultaneously maximize the guest-guest and host-guest interactions. At room temperature, conventionally selective adsorption of CH is observed. The selectivity reversal, structural robustness, and facile regeneration of CUK-1 suggest its potential for producing high-purity CH by temperature-swing sorption.
多孔金属-有机骨架中吸附气体分子之间的相互作用对气体选择性至关重要，但仍未得到充分探索。在这里，我们报告了作为温度函数的超微孔 CUK-1 材料中 CO 和 CH 团簇堆积几何结构的调制。同步辐射 X 射线衍射揭示了 CUK-1 上 CO 和 CH 吸附亲和力的独特温度依赖性逆转，这通过气体吸附和动态突破实验得到了验证，通过一步纯化过程从 CH/CO 的等摩尔混合物中获得了高纯 CH（99.95%）。在低温（<253 K）下，CUK-1 由于形成同时最大化客体-客体和主体-客体相互作用的 CO 四聚体而优先吸附 CO，具有高选择性（>10）和容量（170 cm g）。在室温下，观察到 CH 的传统选择性吸附。CUK-1 的选择性逆转、结构稳健性和易于再生表明其通过温度摆动吸附生产高纯 CH 的潜力。
