ZIF-8 membranes with inborn-suppressed linker mobility sharpen molecular sieving with C ₃ H ₆ /C ₃ H ₈ separation factor above 300.

Suppressing the linker mobility and tuning the aperture size of a MOF membrane is important to achieve promising gas sieving performance. In their communication (DOI: 10.1002/anie.201811638), Wang, Caro et al. propose a double strategy of “stiffening and narrowing” to prepare a ca. 500 nm thin hybrid mixed‐linker ZIF‐7x‐8 membrane with suppressed flexibility and narrowed window aperture by a fast current‐driven synthesis (FCDS) within 20 min, showing significantly sharpened CO₂/CH₄ sieving with a separation factor up to 25.