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Increased Ir–Ir Interaction in Iridium Oxide during the Oxygen Evolution Reaction at High Potentials Probed by Operando Spectroscopy

Czioska, Steffen 1,2; Boubnov, Alexey 1,2; Escalera-López, Daniel; Geppert, Janis ORCID iD icon 3; Zagalskaya, Alexandra; Röse, Philipp ORCID iD icon 3; Saraçi, Erisa 1,2; Alexandrov, Vitaly; Krewer, Ulrike ORCID iD icon 3; Cherevko, Serhiy; Grunwaldt, Jan-Dierk ORCID iD icon 1,2
1 Institut für Katalyseforschung und -technologie (IKFT), Karlsruher Institut für Technologie (KIT)
2 Institut für Technische Chemie und Polymerchemie (ITCP), Karlsruher Institut für Technologie (KIT)
3 Institut für Angewandte Materialien – Keramische Werkstoffe und Technologien (IAM-KWT1), Karlsruher Institut für Technologie (KIT)


The structure of IrO$_{2}$ during the oxygen evolution reaction (OER) was studied by operando X-ray absorption spectroscopy (XAS) at the Ir L$_{3}$-edge to gain insight into the processes that occur during the electrocatalytic reaction at the anode during water electrolysis. For this purpose, calcined and uncalcined IrO$_{2}$ nanoparticles were tested in an operando spectroelectrochemical cell. In situ XAS under different applied potentials uncovered strong structural changes when changing the potential. Modulation excitation spectroscopy combined with XAS enhanced the information on the dynamic changes significantly. Principal component analysis (PCA) of the resulting spectra as well as FEFF9 calculations uncovered that both the Ir L$_{3}$-edge energy and the white line intensity changed due to the formation of oxygen vacancies and lower oxidation state of iridium at higher potentials, respectively. The deconvoluted spectra and their components lead to two different OER modes. It was observed that at higher OER potentials, the well-known OER mechanisms need to be modified, which is also associated with the stabilization of the catalyst, as confirmed by in situ inductively coupled plasma mass spectrometry (ICP-MS). ... mehr

Verlagsausgabe §
DOI: 10.5445/IR/1000136298
Veröffentlicht am 25.11.2021
DOI: 10.1021/acscatal.1c02074
Zitationen: 78
Web of Science
Zitationen: 76
Zitationen: 85
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Angewandte Materialien – Elektrochemische Technologien (IAM-ET1)
Institut für Katalyseforschung und -technologie (IKFT)
Institut für Technische Chemie und Polymerchemie (ITCP)
Institut für Angewandte Materialien – Keramische Werkstoffe und Technologien (IAM-KWT1)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 08.2021
Sprache Englisch
Identifikator ISSN: 2155-5435, 2155-5435
KITopen-ID: 1000136298
HGF-Programm 38.03.02 (POF IV, LK 01) Power-based Fuels and Chemicals
Erschienen in ACS catalysis
Verlag American Chemical Society (ACS)
Band 11
Heft 15
Seiten 10043–10057
Projektinformation SPP 2080; DynaKat-OER (DFG, DFG KOORD, GR 3987/15-1)
Vorab online veröffentlicht am 29.07.2021
Schlagwörter oxygen evolution reaction in situ XAS water splitting iridium oxide dissolution stability modulation excitation spectroscopy flame spray pyrolysis
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