In situ Raman spectroelectrochemistry of graphene oxide

Authors

  • Milan Bouša,

    Corresponding author
    1. Department of Electrochemical Materials, J. Heyrovský Institute of Physical Chemistry of the AS CR, v.v.i., Prague 8, Czech Republic
    2. Faculty of Science, Department of Inorganic Chemistry, Charles University, Prague 2, Czech Republic
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  • Otakar Frank,

    Corresponding author
    1. Department of Electrochemical Materials, J. Heyrovský Institute of Physical Chemistry of the AS CR, v.v.i., Prague 8, Czech Republic
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  • Ivan Jirka,

    1. Department of Electrochemical Materials, J. Heyrovský Institute of Physical Chemistry of the AS CR, v.v.i., Prague 8, Czech Republic
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  • Ladislav Kavan

    1. Department of Electrochemical Materials, J. Heyrovský Institute of Physical Chemistry of the AS CR, v.v.i., Prague 8, Czech Republic
    2. Faculty of Science, Department of Inorganic Chemistry, Charles University, Prague 2, Czech Republic
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Abstract

Electrochemical reduction of few-layer graphene oxide (FLGO) is a simple method for a partial restoration of sp2 network of the graphitic planes damaged by the previous oxidation/exfoliation process, and it is especially interesting for the in situ activation of FLGO in applications for energy conversion and storage. We present a detailed study of the structural evolution of FLGO and also non-oxidized graphene nanoplatelets (GNP) during electrochemical treatment. Two phases of the process can be traced tentatively in the case of FLGO by ex situ X-ray photoelectron spectroscopy and both ex situ and in situ Raman spectroscopy. The first phase is irreversible and dominated by a fast removal of oxygen-bearing functional groups accompanied by a structural ordering, while the second phase shows only a slow irreversible progressive reduction and the major changes in the Raman spectra caused by lattice expansion/contraction upon doping or a mild oxidation/reduction are reversible this time. In GNP, no irreversible reduction is observed, i.e. the first phase is absent, leaving only the reversible variations traceable in the Raman spectra.

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