Water/solid interfaces are of fundamental interest in various fields including geology, metrology, biology, and chemistry. Despite its simple molecular structure the structure and interactions of water with surfaces, which determines wetting and reactivity remain unsolved. The knowledge of this structure at the nanoscale is crucial to understand key properties that determine corrosion, dissolution, and electrochemical processes. This review focuses mainly in the use of Scanning probe Microscopy (SPM) to study water/solid interfaces. One of the differences of SPM from other techniques is the locality of the information. SPM uses a probe tip to scan over the surface, and obtain structural information together with, e.g., electronic, mechanical, and vibrational properties. Because it is not an averaged information over a wide area, as in the case of all the other techniques listed above, detailed investigations of how atomic steps, kinks, and defects residing on the surface influence on the adsorption of molecules are possible.
The review first discusses adsorption configurations, diffusion, aggregation, and dissociation of water molecules on very well defined surfaces such as metals and the formation of larger clusters up to the water monolayer. The discussion moves then to the structure of water monolayers and the formation of ice-like layers induced by the substrate, even at ambient conditions, on relevant samples such as salts and oxides and finally ending by reviewing the formation of thin liquid water films that define wetting properties of the surface. In the last section, we also review recent studies of liquid water near a solid, electrified surface. Here the knowledge obtained from X-ray absorption spectroscopy (XAS) has proved useful for better understanding of atomistic pictures of electrochemical processes, which is challenging by real-space observations using SPM.
Tomoko K. Shimizu,1 Sabine Maier,2 Albert Verdaguer,3 Juan-Jesus Velasco-Velez,4 Miquel Salmeron5
1Faculty of Science and Technology, Keio University, Japan.
2Department of Physics, Friedrich-Alexander-University Erlangen-Nürnberg, Germany.
3Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Spain.
4Department of Inorganic Chemistry, Fritz-Haber-Institute der Max-Planck-Gesellschaft, Germany.
5Lawrence Berkeley National Laboratory, and Materials Science and Engineering Dept., University of California, Berkeley, USA.
Water at surfaces and interfaces: From molecules to ice and bulk liquid
Progress in Surface Science 93(4), 87-107 (2018)
Atomic structure of ice-clusters on Ru(0001)