Regensburg 2025 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 58: Solid-Liquid Interfaces: Reactions and Electrochemistry II

O 58.10: Vortrag

Mittwoch, 19. März 2025, 12:45–13:00, H4

Preparation and Electrochemical Characterization of Metal Bicrystal Electrodes — •Nadine Wölfel, Albert K. Engstfeld, and Timo Jacob — Institute of Electrochemistry, Ulm, DE

The activity of a metal-based electrocatalyst strongly depends on its structural properties, where grain boundaries (GB) can play a significant role. One approach to study the impact of GBs is by varying the grain size of a material, which changes the GB density. In our study we aim at gaining fundamental insights into the atomic scale electrochemical and -catalytic processes at a GB, separating two surfaces with specific crystallographic orientation. We demonstrate how such electrodes can be prepared from Pt wires using the controlled atmosphere flame fusion method [1]. Here, poly-oriented single crystals are formed from two wires, crystallizing as a poly-oriented bicrystal from a common melt. By carefully polishing the poly-oriented crystal along the surface orientation of interest, a planar bicrystal surface with a single GB can be created. The structural properties of the prepared electrodes are determined by Laue X-ray diffraction, scanning electron microscopy (SEM), and electron backscatter diffraction (EBSD) spectroscopy. Electrochemical measurements, such as cyclic voltammetry (CV) are presented, which, based on the features in the CV, provide insights into the available facets and defects. The local electrocatalytic activity of the GB can be elucidated by scanning electrochemical microscopy (SECM) measurements.

[1] FM Schuett et al., Angewandte Chemie, 132 (2020) 13348-13354

Keywords: Bicrystal; grain boundary; cyclic voltammetry; flame fusion method