Issue 27, 2015

Electron transfer kinetics on natural crystals of MoS2 and graphite


Here, we evaluate the electrochemical performance of sparsely studied natural crystals of molybdenite and graphite, which have increasingly been used for fabrication of next generation monolayer molybdenum disulphide and graphene energy storage devices. Heterogeneous electron transfer kinetics of several redox mediators, including Fe(CN)63−/4−, Ru(NH3)63+/2+ and IrCl62−/3− are determined using voltammetry in a micro-droplet cell. The kinetics on both materials are studied as a function of surface defectiveness, surface ageing, applied potential and illumination. We find that the basal planes of both natural MoS2 and graphite show significant electroactivity, but a large decrease in electron transfer kinetics is observed on atmosphere-aged surfaces in comparison to in situ freshly cleaved surfaces of both materials. This is attributed to surface oxidation and adsorption of airborne contaminants at the surface exposed to an ambient environment. In contrast to semimetallic graphite, the electrode kinetics on semiconducting MoS2 are strongly dependent on the surface illumination and applied potential. Furthermore, while visibly present defects/cracks do not significantly affect the response of graphite, the kinetics on MoS2 systematically accelerate with small increase in disorder. These findings have direct implications for use of MoS2 and graphene/graphite as electrode materials in electrochemistry-related applications.

Graphical abstract: Electron transfer kinetics on natural crystals of MoS2 and graphite

Supplementary files

Article information

Article type
28 Apr 2015
11 Jun 2015
First published
12 Jun 2015
This article is Open Access
Creative Commons BY license

Phys. Chem. Chem. Phys., 2015,17, 17844-17853

Author version available

Electron transfer kinetics on natural crystals of MoS2 and graphite

M. Velický, M. A. Bissett, P. S. Toth, H. V. Patten, S. D. Worrall, A. N. J. Rodgers, E. W. Hill, I. A. Kinloch, K. S. Novoselov, T. Georgiou, L. Britnell and R. A. W. Dryfe, Phys. Chem. Chem. Phys., 2015, 17, 17844 DOI: 10.1039/C5CP02490K

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