Effects of Ultraviolet Illumination on Oxygen Interstitial Injection from TiO₂under Liquid Water

Super-band-gap illumination influences the reaction rates of semiconducting oxide surfaces with gases and liquids, so it seems plausible that illumination also affects the analogous rates of surfaces with point defects in the interior of the solid. However, such effects have not been investigated. The present paper fills that gap by employing isotopic self-diffusion measurements to demonstrate ultraviolet-enhanced creation of oxygen interstitial atoms from rutile TiO₂(110) surfaces exposed to liquid water. Illumination affects both the injection rate and the mean diffusion length into the solid, although by different mechanisms. These effects offer a new means to enhance post-synthesis defect tailoring via oxide surfaces.