SurfaceScience21 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 106: Poster Session VIII: Poster to Mini-Symposium: Electrified solid-liquid interfaces III
O 106.7: Poster
Donnerstag, 4. März 2021, 13:30–15:30, P
Electrochemical properties of Ru(0001) - pH effects, anions effects and anodic H2 formation — •Albert K. Engstfeld1, Simon Weizenegger2, Zenonas Jusys2, Joachim Bansmann2, Jakub Drnec3, and R.Jürgen Behm2 — 1Institute of Electrochemistry, Ulm University, Ulm — 2Institute of Surface Chemistry and Catalysis, Ulm University, Ulm — 3ESRF, Grenoble, France
The electrochemical properties of Ru electrodes in aqueous electrolyte are very complex since it interacts strongly with anion species and shows overlapping surface redox processes. Furthermore, it has recently been shown in HClO4 electrolyte that hydrogen adsorbed in the hydrogen evolution region, is desorbed in the positive-going scan by hydroxyl displacement from the surface, to form H2 at potentials more positive than the equilibrium potential of E(1/2H2/H+) = 0 V, instead of forming H+.[1] Here we present the electrochemical properties of Ru(0001) in acid and alkaline electrolytes. The electrodes were prepared under UHV conditions and investigated in an electrochemical flow cell combined with differential electrochemical mass spectrometry (DEMS). With the DEMS data, we provide direct evidence for hydrogen adsorption in H2SO4 electrolyte, which was so far not considered. Additional surface X-Ray diffraction (SXRD) measurements in H2SO4 reveal a strong hysteresis in the potential dependent structural properties and adlayer composition. The herein reported processes are suggested to be characteristic for other strongly interacting metals in general. [1] Scott & Engstfeld, et al, CatSciTechnol, 10 (2020) 6870