SKM 2023 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 69: Poster: Solid-Liquid Interfaces
O 69.2: Poster
Mittwoch, 29. März 2023, 18:00–20:00, P2/EG
When qualitative do not imply quantitative differences: Analyzing the oxygen reduction reaction using first-principles kinetic Monte Carlo simulations. — •Elia Zonta1, Younes Hassani Abdollahi1,2, Karsten Reuter1, and Sebastian Matera1,2 — 1Fritz Haber Institute of the Max Planck Society, Berlin, Germany — 2Institute for Mathematics, Freie Universitaet Berlin, Germany, Germany
The oxygen reduction reaction (ORR) is one of the major bottlenecks for the efficiency of fuel cell devices. We implemented a first-principles kinetic Monte Carlo model for this reaction on Pt(111) using a mechanism from literature [1]. This model possesses two reaction pathways contributing to the electrochemical current density. Disabling one of these pathways results in an identical simulated Tafel plot for this reduced model, as compared to the original model with both pathways being active. One might conclude that the turned off pathway is effectively inactive also in the original model and, especially, has no impact on the qualitative kinetics. However, a detailed analysis reveals that both models lead to very different surface coverages and, particularly, exhibit different rate-determining steps. Thus, these qualitative microkinetic differences do not lead to any quantitative differences in the macrokinetic behavior.
[1] R.F. de Morais, P. Sautet, D. Loffreda, and A.A. Franco, Electrochim. Acta 56, 10842 (2011).