Ab initio simulations of water/metal surfaces

Abstract

Structures and processes at water/metal interfaces play an important technological role in electrochemical energy conversion and storage, photoconversion, sensors or corrosion, just to name a few. However, they are also of fundamental significance as a model system for the study of solid-liquid interfaces which requires to combine concepts from chemistry and physics of crystalline materials and of liquids. Particularly interesting is the fact that the water-water and the water-metal interaction are of similar strength so that the structures at water/metal interfaces result from a competition between these comparable interactions. As water is a polar molecule and water and metal surfaces are both polarizable, furthermore the explicit consideration of the electronic degrees of freedom at water/metal interfaces is mandatory. In principle, ab initio molecular dynamics simulations are thus the method of choice to model water/metal interfaces, but they are computationally still rather demanding. Here, ab initio simulations of water/metal interfaces will be reviewed, starting from static systems such as the adsorption of single water molecules, water clusters and ice-like layers, followed by the properties of liquid water layers at metal surfaces. Technical issues such as the appropriate first-principles description of the water-water and the water-metal interaction will be discussed, also electrochemical aspects will addressed. Finally, more approximate, but numerically less demanding approaches to treat water at metal surfaces from first principles will be briefly discussed.