A Quantitative Structural Investigation of the 0.1 wt % Nb–SrTiO3(001)/H2O Interface

• Published in: Journal of physical chemistry. C Vol. 118; no. 20; pp. 10980 - 10988
• Main Authors: Hussain, H., Torrelles, X., Rajput, P., Nicotra, M., Thornton, G., Zegenhagen, J.
• Format: Journal Article
• Language: English
• Published: American Chemical Society 22.05.2014
• Subjects: Adsorption; Cleaning; Contact; Droplets; Niobium; Surface chemistry; Terraces; Titanium dioxide
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp5034118

Surface X-ray diffraction has been employed to elucidate the structure of the interface between a well-characterized (001) surface of 0.1 wt % Nb–SrTiO3 and liquid H2O. Results are reported for the clean surface, the surface in contact with a drop of liquid water, and the surface after the water droplet has been removed with a flow of nitrogen. The investigation revealed that the clean surface, prepared via annealing in 1 × 10–2 mbar O2 partial pressure, is unreconstructed and rough on a short length scale. The surface is covered with large terraces, the topmost layer of which is either TiO2 or SrO with an area ratio of about 7/3. For the surface in contact with water, our results reveal that associative H2O adsorption is favored for the TiO2-terminated terrace whereas adsorption is dissociative for the SrO-terminated terrace, which validates recent first-principles calculations. After removal of the water droplet, the surface largely resembles the water-covered surface but now with a disordered overlayer of water present on the surface.