Download | - View accepted manuscript: The electrochemical reduction of VO2+ in acidic solution at high overpotentials (PDF, 1.1 MiB)
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DOI | Resolve DOI: https://doi.org/10.1016/j.electacta.2005.05.001 |
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Author | Search for: Gattrell, M.1; Search for: Qian, J.1; Search for: Stewart, C.1; Search for: Graham, P.1; Search for: MacDougall, B.1 |
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Affiliation | - National Research Council of Canada. NRC Institute for Chemical Process and Environmental Technology
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Format | Text, Article |
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Subject | vanadium; High Tafel slope; adsorbed intermediates; carbon electrodes; VRBs |
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Abstract | An investigation has been carried out to attempt to understand the unusually low apparent symmetry factor observed during the reduction of V(5) at higher overpotentials at carbon electrodes (typically <0.13, or >460mVdecade−1). This reaction is of interest because it occurs in vanadium redox-flow batteries (VRBs) during discharge. Polarisation curves were measured using a rotating disk electrode (RDE). The reaction was not solution mass transport controlled, was pH independent (ca from 0 to 1), and the observed Tafel slope was unaffected by V(5) concentration over a range from 0.031 to 280 mM. Electrode double layer capacitance measurements were also carried out in sulphuric acid with and without vanadium. These tests showed that the presence of V(5) caused a suppression of the normal carbon surface quinone pseudocapacitance, as well as the appearance of two new pseudocapacitance peaks, one around 0.175–0.2V and the other around 0.675–0.725V versus SCE. The observed results do not appear consistent with a precipitated film causing diffusion limitations or causing IR drop. A model is developed to try to explain the data, which involves electron transfer through an adsorbed layer of vanadium. |
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Publication date | 2005 |
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In | |
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Language | English |
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Peer reviewed | Yes |
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NRC number | NRCC 52277 |
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NPARC number | 16285554 |
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Export citation | Export as RIS |
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Report a correction | Report a correction (opens in a new tab) |
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Record identifier | e8942587-7f27-4b2e-9580-ff2abe6dac64 |
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Record created | 2010-10-27 |
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Record modified | 2020-04-07 |
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