Dresden 2026 – scientific programme
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O: Fachverband Oberflächenphysik
O 39: Focus Session: Structure and Dynamics of Solvent at Electrochemical Interfaces I
O 39.2: Talk
Tuesday, March 10, 2026, 10:45–11:00, WILL/A317
High-Resolution Hydration Layer Mapping: Does a Hydration Structure above Gold Imply a Clean Surface? — •Antonia Köhler1, Ralf Bechstein1, Michael Reichling2, and Angelika Kühnle1 — 1Bielefeld University, Bielefeld, Germany — 2Institut für Physik, Osnabrück, Germany
Solid-liquid interfaces are pivotal in a broad range of fields, including electrochemistry, catalysis and geochemistry. In electrochemistry, the molecular structure of the electrode-water interface is decisive for understanding and improving electrochemical reactions. In this context, the Au(111) surface constitutes a prototypical model system as gold is believed to be a relatively inert and well-characterized sample material. So far, however, little is known about the hydration structure at the Au(111)-water interface at the molecular level. Here, we present atomic force microscopy data on a gold sample carefully cleaned according to standard electrochemistry preparation recipes. Our three-dimensional atomic force microscopy data reveal a vertically ordered hydration structure with layer-to-layer distances of 0.36 nm as expected for water. Strikingly, despite our extensive cleaning efforts (validated by cyclic voltammetry measurements), our two-dimensional data reveal stripe-like structures at the Au(111)-water interface. The dimensions of these structures differ from the well-known herringbone reconstruction of the gold surface, which is why we interpret them as surface contamination. Our work, hence, demonstrates that the presence of a hydration structure is no evidence for a clean gold surface.
Keywords: Solid-liquid interfaces; Au(111); Electrochemistry; 3D-AFM; Hydration layer