TY - JOUR
T1 - Electron transfer kinetics on mono- and multilayer graphene
AU - Velický, M.
AU - Bradley, D.F.
AU - Cooper, A.J.
AU - Hill, E.W.
AU - Kinloch, I.A.
AU - Mishchenko, A.
AU - Novoselov, K.S.
AU - Patten, H.V.
AU - Toth, P.S.
AU - Valota, A.T.
AU - Worrall, S.D.
AU - Dryfe, R.A.W.
PY - 2014/10/7
Y1 - 2014/10/7
N2 - Understanding of the electrochemical properties of graphene, especially the electron transfer kinetics of a redox reaction between the graphene surface and a molecule, in comparison to graphite or other carbon-based materials, is essential for its potential in energy conversion and storage to be realized. Here we use voltammetric determination of the electron transfer rate for three redox mediators, ferricyanide, hexaammineruthenium, and hexachloroiridate (Fe(CN)63–, Ru(NH3)63+, and IrCl62–, respectively), to measure the reactivity of graphene samples prepared by mechanical exfoliation of natural graphite. Electron transfer rates are measured for varied number of graphene layers (1 to ca. 1000 layers) using microscopic droplets. The basal planes of mono- and multilayer graphene, supported on an insulating Si/SiO2 substrate, exhibit significant electron transfer activity and changes in kinetics are observed for all three mediators. No significant trend in kinetics with flake thickness is discernible for each mediator; however, a large variation in kinetics is observed across the basal plane of the same flakes, indicating that local surface conditions affect the electrochemical performance. This is confirmed by in situ graphite exfoliation, which reveals significant deterioration of initially, near-reversible kinetics for Ru(NH3)63+ when comparing the atmosphere-aged and freshly exfoliated graphite surfaces.
AB - Understanding of the electrochemical properties of graphene, especially the electron transfer kinetics of a redox reaction between the graphene surface and a molecule, in comparison to graphite or other carbon-based materials, is essential for its potential in energy conversion and storage to be realized. Here we use voltammetric determination of the electron transfer rate for three redox mediators, ferricyanide, hexaammineruthenium, and hexachloroiridate (Fe(CN)63–, Ru(NH3)63+, and IrCl62–, respectively), to measure the reactivity of graphene samples prepared by mechanical exfoliation of natural graphite. Electron transfer rates are measured for varied number of graphene layers (1 to ca. 1000 layers) using microscopic droplets. The basal planes of mono- and multilayer graphene, supported on an insulating Si/SiO2 substrate, exhibit significant electron transfer activity and changes in kinetics are observed for all three mediators. No significant trend in kinetics with flake thickness is discernible for each mediator; however, a large variation in kinetics is observed across the basal plane of the same flakes, indicating that local surface conditions affect the electrochemical performance. This is confirmed by in situ graphite exfoliation, which reveals significant deterioration of initially, near-reversible kinetics for Ru(NH3)63+ when comparing the atmosphere-aged and freshly exfoliated graphite surfaces.
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84908439327&partnerID=MN8TOARS
UR - https://pubs.acs.org/doi/10.1021/nn504298r
U2 - 10.1021/nn504298r
DO - 10.1021/nn504298r
M3 - Article
SN - 1936-0851
VL - 8
SP - 10089
EP - 10100
JO - ACS Nano
JF - ACS Nano
IS - 10
ER -