SKM 2023 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 86: Solid-Liquid Interfaces II: Reactions and Electrochemistry I
O 86.4: Vortrag
Donnerstag, 30. März 2023, 16:00–16:15, TRE Phy
Entropic contributions to the stability of electrochemically adsorbed anion layers on Au(111), a microcalorimetric study — •Marco Schönig and Rolf Schuster — Karlsruhe Institute of Technology, Germany
The understanding of the solid/electrolyte interface is detrimental for rationalizing of electrochemical processes. In this contribution we use electrochemical microcalorimetry to study the entropy of formation of the interface for anion (Cl−,Br−,I−,SO42−) adsorption on Au(111) [1]. The entropy of formation of the interface provides information on the structure, order and composition of this interface, which are often used as descriptors in electrochemical processes. The specific adsorption of anions on Au(111) is an important model system, since the nearly ideal polarizability of the gold surface over a large potential window allows to study the formation of surface adlayers up to high surface coverages. We found a negative reaction entropy during the adsorption process, with a distinct minimum around two thirds of the maximum coverage. Additionally, we observed that the course of the reaction entropy vs. potential changes with the employed cation (Li+,K+,Cs+) in solution. We will discuss contributions of the solvent and the electrolyte to the entropy of formation of the interface and provide statistical mechanics models to describe the measured data. We found that it was imperative to include repulsive interactions between the adsorbates to account for the experimental results. [1] M. Schoenig and R. Schuster Phys. Chem. Chem. Phys., 2022, Accepted Manuscript