Facile synthesis of controllable carbonate-doped TiO₂ microspheres for visible light photocatalytic applications

Mesoporous carbonate-doped TiO₂ microspheres were prepared by a facile solvothermal route combining a low-temperature annealing process. XPS, TG, and FTIR analysis revealed the presence of carbonate species on TiO₂ surface, which extended the optical absorption of the TiO₂ microspheres to the visible region. The carbonate-doped T200 microspheres exhibited much higher photocatalytic degradation of MO activity compared with non-doped T400 microspheres under visible light illumination. By adjusting initial titanium precursor concentration and reaction time, the best photocatalytic performance of carbonate-doped T200 microspheres was obtained. In addition, carbonate-doped T200 microspheres also displayed good photocatalytic disinfection efficiency towards Escherichia coli under visible light exposure. Our study revealed that the carbonate-doped TiO₂ microspheres would be applied in the water treatment for the degradation of organic pollutants and disinfection of bacteria.