Cobalt‐Based ZIF Composite Membranes: In Situ Defect Engineering for Enhanced Water Stability and Gas Separation

Abstract Porous coordination polymers with excellent molecular sieving ability, high dispersibility, and good compatibility with engineered polymer matrices hold promise for various industrial applications, such as gas separation and battery separators. Here, an in situ defect engineering approach is proposed for highly processable cobalt (Co)‐based zeolitic imidazolate frameworks (ZIFs) with enhanced molecular sieving ability and water stability. By varying alkylamine (AA) modulators, the pore structures and textural properties of ZIFs can be fine‐tuned. The resulting high‐loading composite membrane exhibits excellent C 3 H 6 /C 3 H 8 separation performance and mechanical properties. This in situ defect engineering approach enables efficient interfacial engineering for high‐performance composite membranes.