Palladium-Assisted Transfer of Graphene for Efficient Hydrogen Isotope Separation

Graphene has been shown to act as an efficient sieve for hydrogen isotope separation since the perfect monolayer graphene is impermeable to almost all atoms and molecules but permeable to protons. Large-area graphene films can be produced by chemical vapor deposition (CVD) and exhibit a considerably high proton–deuteron separation factor of ∼8. However, the performance of the graphene-based membrane is often limited by the presence of cracks and imperfections introduced mainly during the transfer process. Here, we report a simple but effective method to transfer large-area CVD graphene onto commercial Nafion membranes with the aid of palladium thin films and thus fabricate the Pd/Graphene/Nafion composite membranes, which allow a proton–deuteron separation factor up to ∼10. This transfer method avoids the mechanical damage of graphene caused by deformation of the Nafion membrane. There is no need to remove the palladium thin film, and it will act as a catalyst for the reduction of hydrons during electrochemical pumping. The large-area transfer of graphene and fabrication of composite membranes for efficient separation of hydrogen isotopes will promote the development of graphene-based separation technologies.