The oxygen evolution reaction on passive oxide covered transition metal electrodes in alkaline solution. Part III - Iron.
Citation:
Michael E G Lyons, Michael P Brandon `The oxygen evolution reaction on passive oxide covered transition metal electrodes in alkaline solution. Part III ? Iron? in International Journal of Electrochemical Science, 3, (12), 2008, pp 1463 - 1503Download Item:
Lyons Brandon IJES 2008 OER paper 3 3121463.pdf (published (publisher copy) peer-reviewed) 997.3Kb
Abstract:
The kinetics of the oxygen evolution reaction (OER) at passive oxide covered polycrystalline Fe
electrodes in aqueous alkaline solution were examined using both dc steady state polarisation and ac
impedance techniques. It proved difficult to obtain reproducible polarisation data for bright anodes,
and so an electrochemical pre-treatment routine was devised. Upon ageing of a given electrode
specimen, and with application of the pre-treatment regime before each experiment, it was possible to
determine reproducible values of the Tafel slope and the reaction order with respect to OH- ion
activity. The link between OER polarisation behaviour and the changing nature of the passive oxide
film, with repeated electrode pre-treatment and experimental utilisation, was characterised by cyclic
voltammetry. As was previously found for oxidised Co electrodes, it is necessary to admit a dual
energy barrier model in order to rationalise some of the experimental Tafel slope values. By
considering the kinetic data presented here, in tandem with complimentary results obtained for
extensively aged and also for multicycled iron electrodes, a preferred reaction pathway emerges. The
electrode active surface area for the OER has been been estimated using the same current transient
decay technique that we have applied to Ni and Co anodes. On this basis, the ?real? surface area
normalised activity series for the OER amongst the passive oxides of these first row transition metals
is outlined.
Sponsor
Grant Number
Enterprise Ireland
Irish Research Council for Science Engineering and Technology
Higher Education Authority
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http://people.tcd.ie/melyonsDescription:
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Author: LYONS, MICHAEL EDWARD
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Electrochemical Science GroupType of material:
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International Journal of Electrochemical Science3
12
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