Facile fabrication of hierarchical porous TiO2 hollow microspheres with high photocatalytic activity for water purification

Hierarchical porous TiO₂ hollow microspheres were synthesized by a facile approach from a one-step template method. This novel approach avoids tedious multiple steps from conventional template method for fabricating hierarchical porous and hollow microspheres. The as-prepared microspheres were characterized by XRD, SEM, TEM, nitrogen adsorption, and UV-vis DRS. Its photocatalytic activity was demonstrated in the photocatalytic degradation of Rhodamine B. Structural characterization indicates that the as-prepared microspheres had a hollow interior and a hierarchical porous structure with both large and small mesopores on its surface. The average diameters and BET surface areas of the hierarchical porous TiO₂ hollow microspheres were 1.5μm and 117m²/g, respectively. Optical adsorption investigation shows that the hierarchical porous TiO₂ hollow microspheres possessed the optical band gap of 3.42eV. A possible formation mechanism for the hierarchical porous TiO₂ hollow microspheres was discussed. The hierarchical porous TiO₂ hollow microspheres exhibited much higher photocatalytic activity than the commercial P25 TiO₂. In addition, the as-prepared microspheres can be easily recycling for reuse. All these advantages show a bright future for this microspheric photocatalyst in environmental purification.