Abstract:Ultrathin ZIF-8 membranes with a thickness of around 200 nm were prepared by chemical vapour modification of surface chemistry and nanopores of an asymmetric bromomethylated poly(2,6-dimethyl-1,4-phenylene oxide) (BPPO) substrate. The resulting ZIF-8 membranes exhibited exceptional H2 permeance as high as 2.05 × 10(-6) mol m(-2) s(-1) Pa(-1) with high H2/N2 and H2/CO2 selectivities (9.7 and 12.8, respectively).