Electrochemical Functionalization of Graphene-on-Cu(111): Reactivity, Onset Potentials, and Mechanistic Insights

Electrochemical functionalization of graphene facilitates simple and various modifications of graphene properties. However, the scope of the available functional groups and the electrochemical behavior of graphene is not fully understood. The electrochemical reactivity of single crystal and monolayer graphene-on-Cu(111) with various phenyl and alkyl iodides is investigated, and discovered different onset potentials, identifying the extent of the reaction with Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Differential pulse voltammetry (DPV) and density functional theory (DFT) calculations are employed to elucidate the onset potential differences between the phenyl iodides with different substituents. A comprehensive understanding of graphene's electrochemical reactivity is presented.