Berlin 2024 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 18: Solid-Liquid Interfaces I: Structure and Spectroscopy
O 18.12: Vortrag
Montag, 18. März 2024, 17:45–18:00, H 1012
Arrhenius follows Frumkin to describe Atomic Diffusion involved Peaks in Cyclic Voltammograms: the Reversible Place-Exchange on Pt(111) — Jon Bjarke Valbaek Mygind1, Francesc Valls Mascaró2, and •Marcel J. Rost3 — 1Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark — 2Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands — 3Huygens-Kamerlingh Onnes Laboratory, Leiden University, Leiden, The Netherlands
CVs are one of the most powerful tools for the experimental investigation and characterization of electron transfer processes in electrochemistry. Determined by the driving force, thus the potential of the working electrode, electrochemical interfaces can be assessed on their structure as well as activity. As the unique electrochemical fingerprint of a particular system is given by specific (current) peaks in the CV, it is not surprising that great effort is done to understand, describe, and model these peaks analytically. However, the underlying involved thermodynamic and kinetic processes makes this a difficult task, even if specific changes in the fingerprint occur upon change of the voltammogram’s sweep rate. Here we show on the example of the reversible Place-Exchange peak, a precursor in the electrochemical oxidation of the Pt(111) surface, that a combination of a Frumkin isotherm followed by an Arrhenius (atomic) diffusion process delivers a rather good description. All peaks of all CVs, measured with different sweep rates, are simultaneously fitted together with only three (basic description) or six (extended description) fit variables.
Keywords: Cyclic Voltammograms; Frumkin; Arrhenius; Modelling; Place-Exchange