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Operando tracking of oxidation-state changes by coupling electrochemistry with time-resolved X-ray absorption spectroscopy demonstrated for water oxidation by a cobalt-based catalyst film

Pasquini, C.; Liu, S.; Chernev, P.; Gonzalez-Flores, D.; Mohammadi, M. R.; Kubella, P.; Jiang, S.; Loos, S.; Klingan, K.; Sikolenko, V. 1; Mebs, S.; Haumann, M.; Beyer, P.; D’Amario, L.; Smith, R. D. L.; Zaharieva, I.; Dau, H.
1 Karlsruher Institut für Technologie (KIT)


Transition metal oxides are promising electrocatalysts for water oxidation, i.e., the oxygen evolution reaction (OER), which is critical in electrochemical production of non-fossil fuels. The involvement of oxidation state changes of the metal in OER electrocatalysis is increasingly recognized in the literature. Tracing these oxidation states under operation conditions could provide relevant information for performance optimization and development of durable catalysts, but further methodical developments are needed. Here, we propose a strategy to use single-energy X-ray absorption spectroscopy for monitoring metal oxidation-state changes during OER operation with millisecond time resolution. The procedure to obtain time-resolved oxidation state values, using two calibration curves, is explained in detail. We demonstrate the significance of this approach as well as possible sources of data misinterpretation. We conclude that the combination of X-ray absorption spectroscopy with electrochemical techniques allows us to investigate the kinetics of redox transitions and to distinguish the catalytic current from the redox current. Tracking of the oxidation state changes of Co ions in electrodeposited oxide films during cyclic voltammetry in neutral pH electrolyte serves as a proof of principle.

Verlagsausgabe §
DOI: 10.5445/IR/1000136143
Veröffentlicht am 12.08.2021
DOI: 10.1007/s00216-021-03515-0
Zitationen: 10
Web of Science
Zitationen: 9
Zitationen: 10
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Angewandte Geowissenschaften (AGW)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2021
Sprache Englisch
Identifikator ISSN: 1618-2642, 0016-1152, 0372-7920, 0937-0633, 1432-1130, 1618-2650
KITopen-ID: 1000136143
Erschienen in Analytical and Bioanalytical Chemistry
Verlag Springer Verlag
Band 413
Seiten 5395–5408
Vorab online veröffentlicht am 17.07.2021
Nachgewiesen in Web of Science
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