Issue 1, 2018

Bias-dependent local structure of water molecules at a metallic interface

Abstract

Understanding the local structure of water at the interfaces of metallic electrodes is a key issue in aqueous-based electrochemistry. Nevertheless a realistic simulation of such a setup is challenging, particularly when the electrodes are maintained at different potentials. To correctly compute the effect of an external bias potential applied to truly semi-infinite surfaces, we combine Density Functional Theory (DFT) and Non-Equilibrium Green’s Function (NEGF) methods. This framework allows for the out-of-equilibrium calculation of forces and dynamics, and directly correlates to the chemical potential of the electrodes, which is introduced experimentally. In this work, we apply this methodology to study the electronic properties and atomic forces of a water molecule at the interface of a gold surface. We find that the water molecule tends to align its dipole moment with the electric field, and it is either repelled or attracted to the metal depending on the sign and magnitude of the applied bias, in an asymmetric fashion.

Graphical abstract: Bias-dependent local structure of water molecules at a metallic interface

Supplementary files

Article information

Article type
Edge Article
Submitted
16 May 2017
Accepted
03 Oct 2017
First published
11 Oct 2017
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2018,9, 62-69

Bias-dependent local structure of water molecules at a metallic interface

L. S. Pedroza, P. Brandimarte, A. R. Rocha and M.-V. Fernández-Serra, Chem. Sci., 2018, 9, 62 DOI: 10.1039/C7SC02208E

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements