The role of oxygen in mechanochemical wear of graphene

As a protective coating with wide applications due to its outstanding stiffness and chemical inert, graphene often undergoes significantly local stress and chemical etching in practical use conditions, but the degeneration mechanism of graphene under the mechanical and chemical coupling remains largely open. In this work, the experimental measurement demonstrates that the edges of graphene are vulnerable to mechanochemical wear mainly due to the attack from oxygen atoms. Atomic simulations of density functional theory calculations reveal that the C–C networks of graphene are broken through the stress-driven chemical reactions of interfacial bonds formation between graphene edges and the reactive counterface, leading to oxidation unzipping of graphene under low shear stress. The studies suggest the anti-wear performance of graphene edges can be tuned by suppressing interfacial bonds forming.