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

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 degrees C thermal treatment exhibited higher photocatalytic activity than commercial Degussa P25 in the presence of Cr(VI). The possible photodegradation mechanism was also investigated.