SKM 2023 – scientific programme

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O: Fachverband Oberflächenphysik

O 96: Solid-Liquid Interfaces III: Reactions and Electrochemistry II

O 96.1: Talk

Friday, March 31, 2023, 10:30–10:45, TRE Phy

First step of the oxygen reduction reaction on Au(111): A computational study of the electrified metal/water interface — •Elias Diesen, Alexandra M. Dudzinski, Hendrik H. Heenen, Vanessa J. Bukas, and Karsten Reuter — Fritz-Haber-Institut der MPG, Berlin, Germany

While significant insight has been gained in recent years by first-principles simulations of electrochemical processes, crucial methodological challenges remain, especially for accurate determination of reaction energies under operando conditions. One open question is how to represent the constant electrode potential in simulations of an electrified water/metal interface, where the periodic simulation setup requires a constant charge in the simulation cell throughout the reaction. Here we compare different levels of treatment of the electrochemical interface: explicit ab initio molecular dynamics, an implicit solvent model, and a sawtooth-potential electric field in vacuum, for the case of O₂ adsorption on Au(111). We find that all methods agree qualitatively in predicting significantly enhanced O₂ binding at more reducing conditions. Important quantitative differences, however, are also presented and discussed. Umbrella sampling simulations shed light on the underlying free-energy landscape at varying potentials, while assessing the level of detail required in first-principles models of the electric double layer.