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

Wesley T E Van Den Beld,Ageeth A Bol,Jan-Willem Weber,René H J Vervuurt,Mathieu Odijk,Jan C T Eijkel,Albert Van Den Berg

doi:10.1038/srep45080

Wesley T E Van Den Beld, Ageeth A Bol + Show 5 more

Open Access

https://doi.org/10.1038/srep45080

Copy DOI

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.

Highlights

Electrochemistry on graphene is of particular interest due to graphene’s high surface area, high electrical conductivity and low interfacial capacitance
The graphene Fermi level can be probed by its strong Raman signal, giving information about the graphene doping that is potentially caused by adsorbed atoms or molecules[14,15,16,17,18,19,20,21,22]
As a potential application in electrochemical SERS for plasmon-driven catalyst, an electrode surface could be covered by graphene[25,26,27]

Summary

Introduction

Electrochemistry on graphene is of particular interest due to graphene’s high surface area, high electrical conductivity and low interfacial capacitance. FcMeOH is an outer-sphere redox molecule, it is known to adsorb (mostly) reversibly to the graphene surface with a desorption time constant of several minutes[10,31]. In this measured Raman spectrum the G-peak position (in cm−1) is analysed, since this is the most sensitive indicator for the graphene Fermi level and the adsorption level[8,19].

Results

Conclusion