Regensburg 2022 – scientific programme

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O: Fachverband Oberflächenphysik

O 8: Solid-Liquid Interfaces 1: Reactions and Electrochemistry

O 8.7: Talk

Monday, September 5, 2022, 12:15–12:30, S054

Exploring the Limits of Mean-Field Theory in Modeling Thermodynamic Cyclic Voltammograms — •Nicolas Bergmann, Nicolas G. Hörmann, and Karsten Reuter — Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Deutschland

Mean-field theory (MFT) is at the heart of many approaches to simulate materials. Recently, MFT has been used to model thermodynamic cyclic voltammograms (CVs) [1], a standard electrochemical experiment. However, its accuracy limitations in this context remain unclear.

Here, we outline our general ansatz to derive mean field models for thermodynamic CVs based on ab initio DFT calculations of a wide variety of adsorbate configurations [1]. To derive continuous MFT expressions, we use nonparametric Gaussian process regression. We apply our method to assess the fingerprint CV of Cu(100) in iodine-containing, alkaline solutions. The simulations offer new insights into the competitive adsorption between I and OH. Additionally, we benchmark our method by comparing a mean-field model to grand canonical lattice Monte Carlo simulations for the well-studied system Ag(100) in Br-containing electrolyte [2,3].

We analyze in detail the respective (dis-)advantages of both methods.

[1] N.G. Hörmann et al., J. Chem. Theory Comput. 2021, 17, 1782

[2] M.T.M. Koper, J. Electroanal. Chem. 1998, 450, 189-201

[3] M. Nakamura et al., Phys. Rev. B 2011, 84, 165433