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O: Fachverband Oberflächenphysik

O 10: Metal/Water Interfaces: Structure and Reactivity

O 10.8: Vortrag

Montag, 16. März 2015, 16:45–17:00, HE 101

Equilibrium coverage of halides on metals electrodes — •Florian Gossenberger, Tanglaw Roman, and Axel Groß — Institute of Theoretical Chemistry, Ulm University, D-89069 Ulm/Germany

Under acidic conditions, the specific adsorption of anions is an integral part of the formation of the electric double layer at electrochemical metal/electrolyte interfaces. We studied the adsorption of the halides Cl⁻, Br⁻ and I⁻ on Pt(111) and Cu(111) using density functional theory calculations [1]. Based on a thermodynamic approach, the stable equilibrium coverage is linked to the electrode potential without taking the electrochemical environment explicitly into account. Although there are still some quantitative discrepancies with experiment, the qualitative trends derived from the calculations are consistent with experimental observations, in particular as far as the stability of high-coverage halide structures is concerned.

However, under more realistic conditions and low electrode potentials, platinum is always covered with hydrogen, which is always available in an aqueous electrochemical environment. Therefore, mixed coverages of the halides with co-adsorbed hydrogen are considered in the next step to simulate the double layer and the solid-liquid interface at the electrode surface.

[1] Florian Gossenberger, Tanglaw Roman, and Axel Groß, Surf. Sci. 631 (2015), doi: 10.1016/j.susc.2014.01.021 .