Bicontinuous Zeolitic Imidazolate Framework ZIF-8@GO Membrane with Enhanced Hydrogen Selectivity

摘要

Through layer-by-layer (LBL) deposition of a graphene oxide (GO) suspension on a semicontinuous ZIF-8 layer, we have developed a novel bicontinuous ZIF-8@GO membrane. Since only the gaps between the ZIF-8 crystals are sealed by the GO layer due to capillary forces and covalent bonds, the gas molecules can only permeate through the ZIF-8 micropore system (0.34 nm). Therefore, the ZIF-8@GO membranes show high hydrogen selectivity. At 250 ℃ and 1 bar, the mixture separation factors of H_2/CO_2, H_2/N_2, H_2/CH_4, and H_2/C_3H_8 are 14.9, 90.5, 139.1, and 3816.6, with H_2 permeances of about 1.3 × 10~(-7) mol·m~(-2)·s~(-1)·Pa~(-1), which is promising for hydrogen separation and purification by molecular sieving.