Effect of polarization treatment on VII/VIII and VIV/VV kinetics at carbon electrodes

A. Bourke, R. P. Lynch, D. N. Buckley

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

13 Citations (Scopus)

Abstract

It is shown by cyclic voltammetry and electrochemical impedance spectroscopy that polarization treatment of carbon electrodes affects the kinetics of the VII/VIII and the VIV/VV redox reactions. After treatment at potentials more negative than ∼-0.5 V (sat. Hg/Hg2SO4), electrodes are less active for the VII/VIII reactions than after treatment at positive potentials. The activity of the electrode for the VII/VIII reactions is recovered by treatment at positive potentials. However, the converse is observed for the VIV/VV reactions: after treatment at positive potentials electrodes are less active for the VIV/VV reactions than after treatment at negative potentials. Thus, depending on the polarization treatment of each half-cell electrode, either the positive or negative half-cell can be less active (i.e. have slower kinetics). In general, however, the positive half-cell is more active than the negative half-cell: the rate constant of an activated electrode in the positive half-cell is over two orders of magnitude larger than that of a deactivated electrode in the negative half-cell. It is suggested that oxygen species formed on the electrode during anodization inhibit the VIV/VV electrode reaction but enhance the VII/VIII electrode reaction.

Original languageEnglish
Title of host publicationElectrochemical Interfaces in Energy Storage Systems
EditorsK. Edstrom, J. St-Pierre, R. Kostecki, P. Atanassov, D. Guyomard
PublisherElectrochemical Society, Inc.
Pages1-17
Number of pages17
Edition21
ISBN (Electronic)9781607685395
DOIs
Publication statusPublished - 2014
Externally publishedYes
EventSymposium on Electrochemical Interfaces in Energy Storage Systems - 2014 ECS and SMEQ Joint International Meeting - Cancun, Mexico
Duration: 05 Oct 201409 Oct 2014

Publication series

NameECS Transactions
Number21
Volume64
ISSN (Print)1938-6737
ISSN (Electronic)1938-5862

Conference

ConferenceSymposium on Electrochemical Interfaces in Energy Storage Systems - 2014 ECS and SMEQ Joint International Meeting
Country/TerritoryMexico
CityCancun
Period05/10/201409/10/2014

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