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O: Fachverband Oberflächenphysik

O 21: Solid-liquid interfaces: Reactions and electrochemisty II (joint session O/CPP)

O 21.5: Talk

Monday, March 12, 2018, 17:45–18:00, MA 144

A thermodynamic approach on specific anion adsorption via electrochemical Microcalorimetry — •Marco Schönig and Rolf Schuster — Karlsruhe Institute of Technology, Karlsruhe, Germany

The understanding of specific adsorption is of fundamental importance for the description of the electrochemical double-layer. With electrochemical microcalorimetry we measured the reversibly exchanged heat during the anion adsorption/desorption process, which is directly correlated with the reaction entropy of the electrochemical process (1). Using this method we investigated the adsorption of halides (Cl-, Br-, I-) and oxoanions (SO42-/HSO4-, CLO4-) on Au(111) as a function of the surface polarization. For all systems the exchanged heat increased in the adsorption region of the respective anion. A possible explanation may be the configuration entropy of an anion lattice gas.

(1) J. M. Gottfried und R. Schuster. Surface Microcalorimetry. In: Surface and Interface Science. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2016, S. 73-126