New types of graphene-based membranes with molecular sieve properties for He, H2 and H2O

Graphene oxide (GO) and graphene membranes were fabricated by dip-coating a GO dispersion on a specially designed 8YSZ mesoporous membrane. With the use of a reductive thermal treatment at 750 °C, it was possible to obtain a graphene membrane with permselectivities of 215, 80 and 170, for the gas pairs He/N2, H2/CO2 and H2/N2, respectively, and the H2 permeance reached ∼ 7·10−8 mol m−2 s−1 Pa−1. High H2O permeance and selectivity was achieved by processing a GO membrane in air at 300 °C. In pervaporation with H2O/IPA mixtures (5% H2O), the resulting membrane selectively separated H2O (separation factor > 800) and a flux of 4-8 kg m−2 h−1 was achieved at 70 °C.