The electronic structure of iridium oxide electrodes active in water splitting

Pfeifer, V; Jones, TE; Velasco Vélez, JJ; Massué, C; Greiner, MT; Arrigo, R; Teschner, D; Girgsdies, F; Scherzer, M; Allan, J; Hashagen, M; Weinberg, G; Piccinin, S; Hävecker, M; Knop-Gericke, A; Schlögl, R

Abstract

Iridium oxide based electrodes are among the most promising candidates for electrocatalyzing the oxygen evolution reaction, making it imperative to understand their chemical/electronic structure. However, the complexity of iridium oxide's electronic structure makes it particularly difficult to experimentally determine the chemical state of the active surface species. To achieve an accurate understanding of the electronic structure of iridium oxide surfaces, we have combined synchrotron-based X-ray photoemission and absorption spectroscopies with ab initio calculations. Our investigation reveals a pre-edge feature in the O K-edge of highly catalytically active X-ray amorphous iridium oxides that we have identified as O 2p hole states forming in conjunction with IrIII. These electronic defects in the near-surface region of the anionic and cationic framework are likely critical for the enhanced activity of amorphous iridium oxides relative to their crystalline counterparts.

Citation

Pfeifer, V., Jones, T., Velasco Vélez, J., Massué, C., Greiner, M., Arrigo, R., …Schlögl, R. (2015). The electronic structure of iridium oxide electrodes active in water splitting. Physical Chemistry Chemical Physics, 2016(18), 2292-2296. https://doi.org/10.1039/c5cp06997a

• Journal Article Type: Article
• Acceptance Date: Dec 21, 2015
• Online Publication Date: Dec 21, 2015
• Publication Date: Dec 21, 2015
• Deposit Date: Dec 4, 2018
• Publicly Available Date: Dec 4, 2018
• Journal: Physical Chemistry Chemical Physics
• Print ISSN: 1463-9076
• Electronic ISSN: 1463-9084
• Publisher: Royal Society of Chemistry
• Volume: 2016
• Issue: 18
• Pages: 2292-2296
• DOI: https://doi.org/10.1039/c5cp06997a
• Publisher URL: https://doi.org/10.1039/c5cp06997a
• Related Public URLs: https://pubs.rsc.org/en/journals/journalissues/cp#!recentarticles&adv