Rapid Fabrication of High‐Permeability Mixed Matrix Membranes at Mild Condition for CO 2 Capture

Abstract Mixed matrix membranes (MMMs), conjugating the advantages of flexible processing‐ability of polymers and high‐speed mass transfer of porous fillers, are recognized as the next‐generation high‐performance CO 2 capture membranes for solving the current global climate challenge. However, controlling the crystallization of porous metal‐organic frameworks (MOFs) and thus the close stacking of MOF nanocrystals in the confined polymer matrix is still undoable, which thus cannot fully utilize the superior transport attribute of MOF channels. In this study, the “confined swelling coupled solvent‐controlled crystallization” strategy is employed for well‐tailoring the in‐situ crystallization of MOF nanocrystals, realizing rapid (<5 min) construction of defect‐free freeway channels for CO 2 transportation in MMMs due to the close stacking of MOF nanocrystals. Consequently, the fabricated MMMs exhibit approximately fourfold enhancement in CO 2 permeability, i.e., 2490 Barrer with a CO 2 /N 2 selectivity of 37, distinctive antiplasticization merit, as well as long‐term running stability, which is at top‐tier level, enabling the large‐scale manufacture of high‐performance MMMs for gas separation.