Effects of the structure of the Rh³⁺modifier on photocatalytic performances of an Rh³⁺/TiO₂photocatalyst under irradiation of visible light

For a rhodium ion-modified TiO₂(Rh³⁺/TiO₂) photocatalyst responding to visible light, control of the structure of the Rh³⁺modifier and effects of the structures of the Rh³⁺modifier on photocatalytic activities were examined. A TiO₂support was pre-calcined to maintain crystallinity and specific surface area during post-calcination, and the structure of the Rh³⁺modifier for Rh³⁺/TiO₂was changed by post-calcination without causing changes in the crystallinity and specific surface area of the TiO₂support. In mineralization of acetone under irradiation of visible light, the photocatalytic activities of the post-calcined Rh³⁺/TiO₂showed a volcano-like tendency as a function of post-calcination temperature. The results of this study showed that an atomically isolated structure of the Rh³⁺modifier was preferable for high activities and that aggregation of the Rh species led to a decrease in the activities.