Graphene electrochemistry: Edge vs. basal plane sites

Abstract

This work is focused on the topic of electrocatalytic activity of graphene edges. DFT calculations and quantum mechanical theory of charge transfer is used for the investigation of heterogeneous electron transfer kinetics by the example of the oxygen reduction reaction, which is important for electrochemical applications. It is shown that the rate of electron transfer at zigzag edges is ~4 times larger than far from edges. Electron transfer occurs in nonadiabatic regime all over the graphene cluster at distances greater than 5Å. The highest occupied molecular orbital of the graphene cluster makes the main contribution to the electron transfer. Electrocatalytic effect of zig-zag edges is explained by preferential localization of the highly occupied molecular orbital on edges.