Dresden 2026 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 24: Solid-liquid interfaces: Reactions and electrochemistry – Poster

O 24.3: Poster

Montag, 9. März 2026, 18:00–20:00, P2

Predicting Potential-Dependent Binding Energies at the Electrified Metal/Water Interface — •Ann Kathrin Tran, Elias Diesen, Karsten Reuter, and Vanessa J. Bukas — Fritz-Haber-Institut der MPG, Berlin

Density-functional theory studies of electrified metal/water interfaces present many challenges and uncertainties. Even the methodology for computing the thermodynamics of adsorption is not yet well-established, albeit crucial to e.g. heterogeneous electrocatalysis. Here, we discuss common approaches and approximations in a systematic study of electrochemical binding energies. We choose Au(111) as our model system and focus on the adsorption of key intermediates during O₂ electro-reduction. Firstly, we benchmark predictions from three increasingly advanced models of the double layer: an applied saw-tooth potential in vacuum, an implicit solvent model, and explicitly modelled H₂O via ab initio molecular dynamics (AIMD). This comparison disentangles the purely electrostatic energy contribution from stabilization due to explicit H-bonding with the solvent. The latter contribution can be sizeable, yet is only captured by atomistic H₂O in expensive AIMD. We next address the issue of predicting grand-canonical energetics, that is, energies under realistic constant-potential conditions. In this context, we present workfunction information within constant-charge AIMD data, the emerging workfunction-charge relation, as well as different transformation techniques toward constant-potential results. This analysis reveals notable caveats for each approach and highlights the need for further systematic benchmark studies.

Keywords: adsorption energy; solvation; ab initio molecular dynamics; constant-potential; workfunction