Ultrathin Graphene Oxide Membrane with Constructed Tent-shaped Structures for Efficient and Tunable Molecular Sieving

Graphene oxide membrane (GOM) continues to attract intense interest because of its promising two-dimensional channels. However, finely adjusting GOM’s interplanar spacing for tunable molecular separation is still challenging in aqueous solution. Herein, we report tent-shaped interplanar channels that can be constructed by loading SiO2 nanosphere (diameter ≈ 30 nm) into ultrathin GOM (thickness ≈ 20 nm). The tent-shaped structure takes advantage of the augmented space to accelerate the flux while utilizing the preserved circumjacent nano-channel as a molecular sieve. Particularly, by adjusting the density of intercalated SiO2 nanospheres, the concomitant interlayer channel can be finely tuned with molecular-level accuracy. Precise selectivity makes SiO2 loaded GOM (SGM) capable of separating molecules with sub-nanometer differences. At the same time, under the premise of the same rejection, tunable channels endow SGMs with 1.3 - 63 times higher permeability than pristine ultrathin GOM. This tent-shaped structure supplies a new avenue for GOM’s structural regulation, and the impressive performance demonstrates its great potential in the fields of water purification and membrane filtration.