Rapid Exfoliation of Monolayer Graphene from Catalytic Metal Substrate Using Proton Tunneling Effect

Monolayer graphene is known to be permeable to protons (H⁺), while it is impermeable to all other ions, atoms, and molecules. The mechanism that underlies the proton permeability of graphene is still in contention between quantum tunneling and classical thermal transport. Here, we provide direct evidence that the proton permeation of graphene is dominantly caused by the quantum tunneling effect under application of electrochemical potentials. Leveraging this insight, we demonstrate a rapid electrochemical exfoliation of graphene from a metal catalyst surface where the graphene is synthesized by chemical vapor deposition. The processing time for the transfer of graphene from the catalyst surface onto different substrates can be reduced from several hours in the conventional substrate-etching method to only 10 s in this technique.