Porous TiO2 hollow nanospheres: synthesis, characterization and enhanced photocatalytic properties

Abstract

A facile solvothermal process combined with a precursor thermal transformation method has been developed for preparing porous TiO₂ hollow nanospheres with a high surface area and a good thermal stability. The porous TiO₂ hollow spheres were obtained by using TiOSO₄ as a titanium source and carbon nanospheres as a sacrificial template. Their particle size, diameter and morphology can be readily controlled by varying growth parameters, including reaction temperature, time and reagent concentration. The calcination temperature of TiO₂–C core-shell nanospheres was found to have a profound effect on the structure and properties of the final products. The photocatalytic activities of the products were evaluated by the photodegradation of methyl orange (MO). The TiO₂ hollow spheres obtained from 450 °C thermal treatment exhibited higher photocatalytic activity than commercial Degussa P25 in the presence of Cr(VI). The possible photodegradation mechanism was also investigated.