Nanoscopic Structure of the Interface between Reduced TiO2–x(110) and Water Vapor

Abstract

We investigate the interaction between a reduced rutile TiO2–x(110)-(1×4) surface and water vapor at ambient pressures using atomic force microscopy and X-ray photoelectron spectroscopy (AP-AFM and AP-XPS). Our results reveal that water molecules strongly interact with the reduced surface, leading to hydroxylation and localized clustering of water molecules. In defect-rich regions, AFM tip-induced restructuring causes removal of the topmost surface layer, highlighting the lowered cohesive energy of the surface atoms upon hydroxylation. These findings provide new insights into the water adsorption and restructuring mechanisms on reducible transition metal oxides, relevant for catalytic and environmental applications.