Velasco-Vélez, JJ;
Carbonio, EA;
Chuang, CH;
Hsu, CJ;
Lee, JF;
Arrigo, R;
Hävecker, M;
... Jones, TE; + view all
(2021)
Surface Electron-Hole Rich Species Active in the Electrocatalytic Water Oxidation.
Journal of the American Chemical Society
, 143
(32)
pp. 12524-12534.
10.1021/jacs.1c01655.
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Abstract
Iridium and ruthenium and their oxides/hydroxides are the best candidates for the oxygen evolution reaction under harsh acidic conditions owing to the low overpotentials observed for Ru- and Ir-based anodes and the high corrosion resistance of Ir-oxides. Herein, by means of cutting edge operando surface and bulk sensitive X-ray spectroscopy techniques, specifically designed electrode nanofabrication and ab initio DFT calculations, we were able to reveal the electronic structure of the active IrOx centers (i.e., oxidation state) during electrocatalytic oxidation of water in the surface and bulk of high-performance Ir-based catalysts. We found the oxygen evolution reaction is controlled by the formation of empty Ir 5d states in the surface ascribed to the formation of formally IrV species leading to the appearance of electron-deficient oxygen species bound to single iridium atoms (μ1-O and μ1-OH) that are responsible for water activation and oxidation. Oxygen bound to three iridium centers (μ3-O) remains the dominant species in the bulk but do not participate directly in the electrocatalytic reaction, suggesting bulk oxidation is limited. In addition a high coverage of a μ1-OO (peroxo) species during the OER is excluded. Moreover, we provide the first photoelectron spectroscopic evidence in bulk electrolyte that the higher surface-to-bulk ratio in thinner electrodes enhances the material usage involving the precipitation of a significant part of the electrode surface and near-surface active species.
| Type: | Article |
|---|---|
| Title: | Surface Electron-Hole Rich Species Active in the Electrocatalytic Water Oxidation |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1021/jacs.1c01655 |
| Publisher version: | http://dx.doi.org/10.1021/jacs.1c01655 |
| Language: | English |
| Additional information: | © 2021 The Authors. Published by American Chemical Society. This is an open access article under the CC BY 4.0 license Attribution 4.0 International (https://creativecommons.org/licenses/by/4.0/) |
| Keywords: | Oxidation state, Two dimensional materials, Electrodes, Oxidation, Transition metals |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Chemical Engineering |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10134357 |
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