Effect of the number of graphene layers on the electron transfer kinetics at metal/graphene heterostructures

Abstract

We theoretically investigated the kinetics of outer-sphere electron transfer (ET) at graphene with different number of layers in the presence and absence of metal substrates using density functional theory (DFT) calculations. It is shown that the experimental data on the electrocatalytic activity of the metal substrate for few-layer graphene can be explained under the assumption of the nonadiabatic electron transfer. However, the electron transfer at the metal-supported single-layer graphene is likely adiabatic. The enhanced electron transfer in the presence of the metal substrate is explained by the hybridization of the metal and graphene electronic states, which provides more efficient interaction of the metal substrate with the reactant near the graphene surface.