Regensburg 2025 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 27: Solid-Liquid Interfaces: Reactions and Electrochemistry I
O 27.4: Vortrag
Dienstag, 18. März 2025, 11:15–11:30, H4
Field-induced water autoionization in two- and three-dimensions — •Yair Litman and Angelos Michaelides — University of Cambridge, Cambridge, U. K.
The behaviour of water under an electric field critically influences the performance of numerous energy conversion and storage devices and remains a subject of active investigation. Recent experiments have shown that at electric field strengths exceeding 108V/Å, the water dissociation reaction (2H2O ⇌ H3O+ + OH−) is significantly accelerated, a phenomenon known as the (secondary) Wien effect [1].
In this work, we employ the modern theory of polarization to perform (periodic) ab initio molecular dynamics simulations of water under external electric fields, both in bulk and under nanoconfinement. Our simulations reveal that electric fields facilitate the water dissociation reaction by not only reducing the enthalpy of the reaction but also by increasing the corresponding entropic contribution. Furthermore, we demonstrate that geometric constraints imposed by a 2D confinement can amplify the field-induced reaction rates. These findings highlight the importance of entropy changes in field-induced aqueous reactions and propose nanoconfinement as a promising avenue for enhancing the efficiency of electrocatalytic reactions.
[1] J. Cai. et al., Nat. Commun 13, 5776 (2022)
Keywords: Water; Wien effect; water autoionization