Regensburg 2013 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 58: Poster Session III (Solid-liquid interfaces; Scanning probe and other methods; Electronic structure theory; Spin-orbit interaction)
O 58.85: Poster
Mittwoch, 13. März 2013, 18:15–21:45, Poster B1
Influence of electrochemical adsorption on the conductive properties of thin platinum films in sulfuric acid — •Damian Bürstel and Detlef Diesing — Universität Duisburg - Essen, Fakultät für Chemie, Universitätsstrasse 2, D - 45141 Essen, Germany
The electrochemical hydrogen and oxygen reactions on platinum surfaces in acidic solution are still of great interest for electrocatalytic as well as for energy conversion research. In modern applications platinum is used in form of a few tens of nanometer thick metal films or as nanoparticles. At these dimensions one must be aware of the conductive properties of the metal film and particle and the influence of the changing metal–electrolyte interface on these properties during the electrochemical reactions.
The conductance of a thin platinum film on glass was measured by DC methods as well as AC methods at different frequencies simultaneously to cyclovoltammetric experiments in 0.5 M sulfuric acid. For the oxidation region the film conductance is mainly affected by the volumetric oxidation and reduction of the film and less effected by the metal–liquid interface properties. At hydrogen free platinum surfaces in the oxidation as well as in the electrochemical double-layer region a considerably high phase shift of the conductance with respect to the driving voltage across the film exists in AC measurements. In the course of hydrogen adsorption at EHESS < 0.4 V a conduction parallel to the metal–liquid interface sets in with a low phase shift.