Tuning Spatial Distribution of Surface Hydroxyls on a Metal-Supported Single-Layer Silica.

Using scanning tunneling microscopy and infrared reflection absorption spectroscopy, we studied adsorption of water on a single-layer silicatene grown on Ru(0001). Surface hydroxylation occurs exclusively on defect sites, resulting in isolated silanols (Si-OH). By modifying the defect structure of the overlayer, we have provided a means of tuning spatial distribution of surface hydroxyls to fabricate periodic arrays of silanols on a metal-supported single-layer silicatene. We have visualized the surface hydroxyls directly with atomic resolution to determine their preferential adsorption sites, which involve Si at the junction nodes of three nonequivalent silica polygons. Our results open up the possibility of patterning surface hydroxyls via the engineering of nanometer scale defect sites, which may then serve as potential templates for supported active species on oxide surfaces.