In-situ Raman spectroscopy to elucidate the influence of adsorption in graphene electrochemistry

Abstract

Electrochemistry on graphene is of particular interest due to graphene's high surface area, high electrical conductivity and low interfacial capacitance. Because the graphene Fermi level can be probed by its strong Raman signal, information on the graphene doping can be obtained which in turn can provide information on adsorbed atoms or molecules. For this paper, the adsorption analysis was successfully performed using three electroactive substances with different electrode interaction mechanisms: hexaammineruthenium(III) chloride (RuHex), ferrocenemethanol (FcMeOH) and potassium ferricyanide/potassium ferrocyanide (Fe(CN)6). The adsorption state was probed by analysing the G-peak position in the measured in-situ Raman spectrum during electrochemical experiments. We conclude that electrochemical Raman spectroscopy on graphene is a valuable tool to obtain in-situ information on adsorbed species on graphene, isolated from the rest of the electrochemical behaviour.