Modulated Cr(III) oxidation in KOH solutions at a gold electrode: competition between disproportionation and stepwise electron transfer

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Publication Type Manuscript
School or College College of Mines & Earth Sciences
Department Metallurgical Engineering
Creator Miller, Jan D.
Other Author Jin, Wei; Moats, Michael S.; Zheng, Shili; Du, Hao; Zhang, Yi
Title Modulated Cr(III) oxidation in KOH solutions at a gold electrode: competition between disproportionation and stepwise electron transfer
Date 2011-01-01
Description The electrochemical oxidation of aqueous Cr(III) was examined using cyclic voltammetry with a polycrystalline Au electrode in KOH solutions of varying pH and Cr(III) concentration. The mechanism and kinetics for the oxidation of Cr(III) is a quasi-reversible diffusion-controlled reaction and is largely dependent on the solution pH. The reaction mechanism is initiated by an irreversible electrochemical electron transfer to form Cr(IV) which is the rate-determining step (RDS). Following the RDS, subsequent oxidation of Cr to its hexavalent state occurs by the disproportionation of Cr(IV) at low KOH concentrations and electron transfer at high KOH concentrations due to the involvement of OH- in the disproportionation reaction. As the solution pH increases, the Cr(III) oxidation peak potential shifts negatively owing to the involvement of OH- in the RDS. The competitive adsorption of OH- and CrO2- on the electrode surface also plays an important role in the oxidation behavior.
Type Text
Publisher Elsevier
Volume 56
Issue 24
First Page 8311
Last Page 8318
DOI http://dx.doi.org/10.1016/j.electacta.2011.06.110
Language eng
Bibliographic Citation Jin, W., Moats, M. S., Zheng, S., Du, H., Zhang, Y., & Miller, J. D. (2011). Modulated Cr(III) oxidation in KOH solutions at a gold electrode: competition between disproportionation and stepwise electron transfer. Electrochimica Acta, 56(24), 8311-8.
Rights Management (c) Elsevier ; Reprinted from Jin, W., Moats, M. S., Zheng, S., Du, H., Zhang, Y., & Miller, J. D. (2011). Modulated Cr(III) oxidation in KOH solutions at a gold electrode: Competition between disproportionation and stepwise electron transfer. Electrochimica Acta, 56(24), 8311-8.
Format Medium application/pdf
Format Extent 2,240,327 bytes
Identifier uspace,17031
ARK ark:/87278/s6n01r6k
Setname ir_uspace
Date Created 2012-07-26
Date Modified 2021-05-06
ID 707574
Reference URL https://collections.lib.utah.edu/ark:/87278/s6n01r6k
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