Photo-induced Surface Dissolution of Titanium Dioxide Particles in Sulfuric Acid Solution

Abstract

The surface structure of TiO₂ particles was changed by illumination in a sulfuric acid solution. Small dimples with a size less than a few tens of nm were formed when the surface of the particles was modified by platinum. Particles without the platinum modification did not show any change in their surface structure. A structural change was also observed when the particles were positively polarized in a sulfuric acid solution under illumination on an optically transparent glass electrode. The results suggest that the density of the photogenerated holes in the particles play an important role in inducing the photoetching reaction of TiO₂ particles.