Highly Permeable and Selective Crumpled Graphene Oxide Membranes for Hydrogen Separation

Two-dimensional (2D) materials-based membranes especially graphene oxide (GO) membranes have been proven to be the promising materials for the gas separation application due to their easy operation, energy-saving and high efficiency. The intrinsic in-plane defects, consisting of the nanopores in flakes and grain boundaries, and plane-to-plane interlayer spacing provide the lamellar GO membranes with molecules transport pathway, which determine the permeability and selectivity of the membrane. The dense lamellar structure and tortuous permeation path endow the lamellar GO membrane with high selectivity but hinder the gas molecules passing through, which limits the application of GO membranes in industrial fields. Herein, inspired by the enhanced gas exchange of crumpled alveolus in human body, a novel crumpled structure of GO membranes was introduced and fabricated facilely by using the heat-induced shrink polymer. The crumpled features endowed the membranes with much larger gas-accessible area and therefore higher H₂ permeability about 2.1×10⁴ Barrer with decent H₂/CO₂ selectivity around 90, which surpassed the state-of-the-art membranes. The intrinsic selective lamellar layers and loose disordered flake alignments constituted the anisotropic multidomain structure which guaranteed high permeability with excellent selectivity. The fabricated crumpled GO membranes were also tested in severe environments and exhibited good thermal-stability and humidity-stability. The accessibility for mass-production and long-term stability made the crumpled GO membranes become potential in industrial exploitation.