A spontaneous dissolution approach to carbon coated TiO ₂ hollow composite spheres with enhanced visible photocatalytic performance

TiO ₂ /carbon hollow composite spheres with mesoporous structure were successfully prepared by using a conventional hard template method but without an on-purpose etching process to remove the core material. A possible surface-protected dissolution mechanism was proposed to account for the spontaneous dissolution of the silica core. The thickness of carbon layer could be well controlled by adjusting the concentration of glucose in the hydrothermal reaction. Moreover, the as-prepared TiO ₂ /C hollow spheres had remarkable light absorption in the visible region. As compared with the SiO ₂ @TiO ₂ solid spheres prepared without the addition of glucose, the TiO ₂ /C hollow spheres exhibited enhanced photocatalytic efficiency for the visible-light photodegradation of Rhodamine B.