Regensburg 2025 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 65: Solid-Liquid Interfaces: Reactions and Electrochemistry III
O 65.7: Vortrag
Mittwoch, 19. März 2025, 16:30–16:45, H6
Influence of pH and Electrolyte Flow on the Oxidation of Ni anodes at High Overpotentials — •Justus Leist1, Timo Jacob1,2,3, and Albert K. Engstfeld1 — 1Institute of Electrochemistry, Ulm, Germany — 2Helmholtz-Institute-Ulm (HIU), Ulm, Germany — 3Karlsruhe Institute of Technology, Karlsruhe, Germany
The electrocalalytic splitting of aqueous electrolytes is typically impeded by the sluggish kinetics of the oxygen evolution reaction (OER). Ni-based catalysts are considered as cost-effective alternatives to the currently used rare metal oxides, such as Ir or Ru. While the fundamental properties of Ni have been studied intensively usually at or around the onset potential for the OER, here we study the OER activity at high overpotentials, which are more closely related to application.
The OER characteristics are studied by means of cyclic voltammetry and polarization curves using Ni electrodes in alkaline solutions. Depending on the experimental conditions, electrolyte pH and flow, the current voltage traces show several features at high overpotentials, which can be attributed to the pH-dependent change in OER kinetics. Based on additional in-situ Raman spectroscopy and electrochemical quartz crystal microbalance measurements we discuss possible structures formed and the degradation of the Ni electrodes under these conditions.
Keywords: OER; Ni; Overpotential; Raman; QCM