Ultra-Tuning of the Aperture Size in Stiffened ZIF-8_Cm Frameworks with Mixed-Linker Strategy for Enhanced CO2/CH4 Separation

作者：Hou, Qianqian; Wu, Ying; Zhou, Sheng; Wei, Yanying^*; Caro, Jurgen^*; Wang, Haihui^*

来源：Angewandte Chemie - International Edition, 2019, 58(1): 327-331.

DOI：10.1002/anie.201811638

• fast current-driven synthesis
• gas separation
• mixed-linker
• MOF membrane
• zeolitic imidazolate framework

ZIF-8 membrane has the potential for CO2/CH4 separation based on size exclusion. But if traditionally prepared by solvothermal methods, it shows only negligible selectivity due to the linker mobility. Here, approximate to 500 nm-thin hybrid ZIF-7(x)-8 membranes with suppressed linker mobility and narrowed window aperture are prepared by a fast current-driven synthesis (FCDS) within 20 min. The in situ electric field during FCDS allows the formation of stiffened ZIF-8_Cm as parent skeleton and the mixed-linker strategy is applied to narrow the aperture size simultaneously. The ZIF-7(22)-8 membrane shows significantly sharpened molecular sieving for CO2/CH4 with a separation factor above 25, which soared tenfold compared with other unmodified ZIF-8 membranes. Additionally, the membrane shows exceptional separation performance for H-2/CH4 and CO2/N-2, with separation factors of 71 and 20, respectively. After 180 h temperature swing operation, it still maintains the excellent separation performance.

• 出版日期2019-1-2
• 单位华南理工大学