Growing ZIF‐8 Seeds on Charged COF Substrates toward Efficient Propylene‐Propane Separation Membranes

Abstract We report a covalent organic framework (COF) induced seeding strategy to fabricate metal–organic framework (MOF) membranes. Contrary to graphene oxide nuclei‐depositing substrate, COF substrate has uniform pore size, high microporosity and abundant functional groups. We designed a series of charged COF nanosheets to induce the formation of ZIF‐8@COF nanosheet seeds with high aspect ratio over 150, which were readily processed into a compact and uniform seed layer. The resulting ZIF‐8 membranes with thickness down to 100 nm exhibit an ultrahigh C 3 H 6 /C 3 H 8 separation performance and superior long‐term stability. Our strategy is also validated by fabricating ultrathin ZIF‐67 and UiO‐66 membranes.