Regensburg 2022 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 20: Poster
DS 20.4: Poster
Mittwoch, 7. September 2022, 16:00–18:00, P3
In situ surface X-ray diffraction studies at high temperatures of Co oxide model catalysts for electrochemical water splitting — •Carl Hendric Scharf1, Canrong Qiu1, Jochim Stettner1, Olvido Irrazábal-Moreda2, Mathilde Bouvier3, Fouad Maroun3, and Olaf Magnussen1 — 1Institute of Experimental and Applied Physics, Kiel, Germany — 2European Synchrotron Radiation Facility (ESRF), Grenoble, France — 3Physique de la Matière Condensée, Ecole Polytechnique, Palaiseau, France
The development of low-cost electrocatalysts for electrochemical water splitting is of great interest for hydrogen technology. Among the best precious-metal-free electrode materials for the anodic oxygen evolution reaction (OER) in alkaline electrolysis are Co oxides such as Co3O4 and CoOOH. It was shown previously that a sub-nm thick CoOx(OH)y skin layer is formed in the pre-OER potential range, which forms the active phase during OER. Furthermore, reversible and irreversible structural changes in the oxide bulk were detected in the pre-OER regime. So far the vast majority of publications on Co oxide OER electrolysis have been performed at room temperature. We present first results up to 60∘C (typ. operating temperatures of commercial electrolysers). Using operando surface X-ray diffraction Co3O4 and CoOOH epitaxial films electrodeposited on Au(111) were studied in 0.1M NaOH at Petra III, Desy. These data are correlated with the electrochemical properties, determined by Cyclic Voltammetry and Optical Reflectivity, in order to provide insights into the temperature-dependence of skin layer thickness, bulk lattice changes and the stability of the oxides.