Inside Cover: Ultra‐Tuning of the Aperture Size in Stiffened ZIF‐8_Cm Frameworks with Mixed‐Linker Strategy for Enhanced CO 2 /CH 4 Separation (Angew. Chem. Int. Ed. 1/2019)

Suppressing the linker mobility and tuning the aperture size of a MOF membrane is important to achieve promising gas sieving performance. In their communication on page 327 ff., Y. Wei, J. Caro, H. Wang et al. proposed a double strategy of “stiffening and narrowing” to prepare a roughly 500 nm thin hybrid mixed-linker ZIF-7x-8 membrane with suppressed flexibility and narrowed window aperture through a fast current-driven synthesis (FCDS). The membrane shows significantly sharpened CO2/CH4 sieving with a separation factor up to 25.