Regensburg 2016 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 72: Solid-Liquid Interfaces: Reactions and Electrochemistry

O 72.7: Poster

Mittwoch, 9. März 2016, 18:15–20:30, Poster A

Cu surface reactions in hydrochloric solution probed on the atomic scale by polarization optical methods and STM — •Christoph Cobet, Gholamreza Barati, Vladyslav Solokha, and Kurt Hingerl — Center for Surface- and Nanoanalytics (ZONA), Johannes Kepler Universität, Altenbergerstr 69, A-4040, Linz, Austria

Electrochemical reactions on metal electrodes have been in the focus of many scientific studies and Cu is probably the most investigated example. The interest on Cu is motivated by questions concerning e.g. corrosion, electro-polishing, and catalytic processes. It is evident that a fundamental understanding requires knowledge about the microscopic occurrence of the surface in electrolyte. But unfortunately, most of the classical surface sensitive techniques as used in UHV cannot be applied in liquid environments and thus many details about surface structures are still under discussion. In the presented work we combine reflection anisotropy spectroscopy and a homemade electrochemical scanning tunneling microscope in order to study Cu(110) single crystals in hydrochloric solutions. With this approach we could monitor the local appearance as well as the dynamics of interface transformations/reactions on atomic scale. In particular it was possible to correlate anodic Faraday-current maxima with structural transformation. Accordingly, the Cl adsorption minimizes the surface energy by a formation of monoatomic steps parallel to the [001] direction which finally ends in a faceting of the surface. These surface modifications may influence also the rate of the known Cu dissolution at increasing anodic potentials.