Influence of defects in graphene on electron transfer kinetics: The role of the surface electronic structure

The kinetics of an outer-sphere nonadiabatic electron transfer reaction at the defective graphene is theoretically investigated. Different intrinsic and extrinsic point defects were analyzed. The band structure from DFT, in combination with the Gerischer model, was used for the predictions. Calculations were done taking into account the quantum capacitance of the surface for the correct prediction of alignment and occupation of graphene electronic states upon contact with an electrolyte. We have shown that an electrochemical property of graphene largely depends on defect type due to differences in the electronic structure induced by defects. Due to small graphene quantum capacitance, the electron transfer kinetics can be modulated by changes in the double-layer capacitance. The deviations of the potential dependence of the rate constant from the Butler-Volmer kinetics are predicted.