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Kinetics of oxygen evolution at alpha-Fe2O3 photoanodes: a study by photoelectrochemical impedance spectroscopy
journal contribution
posted on 2014-09-04, 14:25 authored by Upul Wijayantha-Kahagala-Gamage, Sina Saremi-YarahmadiSina Saremi-Yarahmadi, Laurence M. PeterPhotoelectrochemical Impedance Spectroscopy (PEIS) has been used to characterize the kinetics of electron transfer and recombination taking place during oxygen evolution at illuminated polycrystalline α-Fe2O3 electrodes prepared by aerosol-assisted chemical vapour deposition from a ferrocene precursor. The PEIS results were analysed using a phenomenological approach since the mechanism of the oxygen evolution reaction is not known a priori. The results indicate that the photocurrent onset potential is strongly affected by Fermi level pinning since the rate constant for surface recombination is almost constant in this potential region. The phenomenological rate constant for electron transfer was found to increase with potential, suggesting that the potential drop in the Helmholtz layer influences the activation energy for the oxygen evolution process. The PEIS analysis also shows that the limiting factor determining the performance of the α-Fe2O3 photoanode is electron–hole recombination in the bulk of the oxide.
Funding
EPSRC and Loughborough University Materials Research School
History
School
- Science
Department
- Chemistry
Published in
PHYSICAL CHEMISTRY CHEMICAL PHYSICSVolume
13Issue
12Pages
5264 - 5270 (7)Citation
WIJAYANTHA, K.G.U., SAREMI-YARAHMADI, S. and PETER, L.M., 2011. Kinetics of oxygen evolution at alpha-Fe2O3 photoanodes: a study by photoelectrochemical impedance spectroscopy. Physical Chemistry Chemical Physics, 13 (12), pp. 5264 - 5270.Publisher
© Royal Society of ChemistryVersion
- VoR (Version of Record)
Publisher statement
This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/Publication date
2011Notes
Closed access. This article was published in the journal, Physical Chemistry Chemical Physics [© Royal Society of Chemistry] and the definitive version is available at: http://dx.doi.org/10.1039/C0CP02408BISSN
1463-9076Publisher version
Language
- en