Enhancing graphene's resistance to oxidative corrosion by positive charge doping: A DFT view

Abstract

Although graphene has been widely used as a protective coating for many applications, the failure mechanism and the strategy to improve its resistance to the chemical etching is largely unknown. We herein have comparatively studied the generally oxidative corrosion process of neutral and positive-charge-doping (PCD) graphene via DFT (density functional theory) simulations. It is found that the positive-charge-doping (PCD) generally enhances the protecting ability of graphene for substrates from reactive environments. The C-network breakdown of graphene due to oxidative etching goes through three stages: the formation of oxidative corrosion crystal nucleus (OCCN), subsequent formation and expansion of oxidative lined defect (OLD), then the generation and extension of oxidative corrosion crack (OCC). Comparing to the neutral or negative charge doping, PCD decreases the electronic reactivity and thus suppresses the oxygen atoms diffusing on graphene of the rate-limiting step, especially in the stage of OCCN nucleation. Our work indicates a possible strategy to improve the resistance to oxidative corrosion (ROC) of graphene via positive charge doping. This protection enhancement of graphene can be achieved taking advantages of the electron capture of the neighboring substrates, reactive environments or external gate voltage in applications.