Mesoporous Zeolitic Imidazolate Framework‐8 Nanoplates Mixed‐Matrix Membranes for Superior Gas Transport

In this article, high‐aspect‐ratio zeolitic imidazolate framework‐L (ZIF‐L) nanoplates were synthesized using polyvinylpyrrolidone (PVP) as a surfactant and subsequently transformed into mesoporous ZIF‐8 (mZIF‐8) through a crystalline reorganization process involving etching and recrystallization in ethanol/N,N‐dimethylformamide cosolvents. The resulting ZIF‐L and mZIF‐8 nanoplates possessed an average particle size of approximately 5 × 1 µm. This conversion significantly enhanced the Brunauer–Emmett–Teller surface area by generating interconnected meso‐ and microporous domains. The mZIF‐8 nanoplates were incorporated into a polymer of intrinsic microporosity‐1 (PIM‐1) matrix to fabricate mixed‐matrix membranes (MMMs) with filler loadings of 10, 20, 30, and 40 wt%. The membrane containing 40 wt% mZIF‐8 nanoplates exhibited outstanding gas permeation performance, with H 2 and CO 2 permeabilities of 9275 and 9826 Barrer, respectively, corresponding to enhancements of 430% and 240% over pristine PIM‐1. Of note, it revealed CO 2 /N 2 and CO 2 /CH 4 selectivities of approximately 20 and 15, and H 2 /N 2 and H 2 /CH 4 selectivities of 17 and 13. These gas permeability improvements are attributed to the mesoporous structure and anisotropic morphology of the ZIF‐8 nanoplates, which enable rapid gas transport through metal–organic framework (MOF)–MOF percolation pathways and nonselective diffusion regions. Additionally, the mesoporous MMMs effectively suppressed CO 2 ‐induced plasticization and mitigated physical aging, demonstrating improved long‐term stability. These findings underscore the importance of structural and morphological engineering of MOF fillers in designing high‐performance and durable MMMs for advanced gas separation applications.