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A new view of electrochemistry at highly oriented pyrolytic graphite
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Patel, Anisha N., Guille, Manon (Collignon), O'Connell, Michael A., (Researcher in chemistry), Hung, Wendy O. Y., McKelvey, Kim M. (Kim Martin), Macpherson, Julie V. and Unwin, Patrick R. (2012) A new view of electrochemistry at highly oriented pyrolytic graphite. Journal of the American Chemical Society, Volume 134 (Number 49). pp. 20117-20130. doi:10.1021/ja308615h ISSN 0002-7863.
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WRAP_Patel, JACS, 2012.pdf - Accepted Version Download (2853Kb) | Preview |
Official URL: http://dx.doi.org/10.1021/ja308615h
Abstract
Major new insights on electrochemical processes at graphite electrodes are reported, following extensive investigations of two of the most studied redox couples, Fe(CN)64–/3– and Ru(NH3)63+/2+. Experiments have been carried out on five different grades of highly oriented pyrolytic graphite (HOPG) that vary in step-edge height and surface coverage. Significantly, the same electrochemical characteristic is observed on all surfaces, independent of surface quality: initial cyclic voltammetry (CV) is close to reversible on freshly cleaved surfaces (>400 measurements for Fe(CN)64–/3– and >100 for Ru(NH3)63+/2+), in marked contrast to previous studies that have found very slow electron transfer (ET) kinetics, with an interpretation that ET only occurs at step edges. Significantly, high spatial resolution electrochemical imaging with scanning electrochemical cell microscopy, on the highest quality mechanically cleaved HOPG, demonstrates definitively that the pristine basal surface supports fast ET, and that ET is not confined to step edges. However, the history of the HOPG surface strongly influences the electrochemical behavior. Thus, Fe(CN)64–/3– shows markedly diminished ET kinetics with either extended exposure of the HOPG surface to the ambient environment or repeated CV measurements. In situ atomic force microscopy (AFM) reveals that the deterioration in apparent ET kinetics is coupled with the deposition of material on the HOPG electrode, while conducting-AFM highlights that, after cleaving, the local surface conductivity of HOPG deteriorates significantly with time. These observations and new insights are not only important for graphite, but have significant implications for electrochemistry at related carbon materials such as graphene and carbon nanotubes.
Item Type: | Journal Article | ||||
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Subjects: | Q Science > QD Chemistry | ||||
Divisions: | Faculty of Science, Engineering and Medicine > Science > Chemistry Faculty of Science, Engineering and Medicine > Research Centres > Molecular Organisation and Assembly in Cells (MOAC) |
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Library of Congress Subject Headings (LCSH): | Electrochemistry, Graphite, Electrodes, High resolution electron microscopy, Nanotubes, Graphene | ||||
Journal or Publication Title: | Journal of the American Chemical Society | ||||
Publisher: | American Chemical Society | ||||
ISSN: | 0002-7863 | ||||
Official Date: | November 2012 | ||||
Dates: |
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Volume: | Volume 134 | ||||
Number: | Number 49 | ||||
Page Range: | pp. 20117-20130 | ||||
DOI: | 10.1021/ja308615h | ||||
Status: | Peer Reviewed | ||||
Publication Status: | Published | ||||
Access rights to Published version: | Restricted or Subscription Access | ||||
Date of first compliant deposit: | 24 December 2015 | ||||
Date of first compliant Open Access: | 24 December 2015 | ||||
Funder: | Engineering and Physical Sciences Research Council (EPSRC), European Research Council (ERC), Marie Curie Intra-European Fellowship (IEF), Syngenta Seeds Ltd., Science City Research Alliance, Advantage West Midlands (AWM), European Regional Development Fund (ERDF) | ||||
Grant number: | EP/H023909/1 (EPSRC), EP/F064861/1 (EPSRC), ERC-2009-AdG 247143-QUANTIF (ERC), |
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