Hierarchical TiO 2 spheres: facile fabrication and enhanced photocatalysis

Hierarchical TiO 2 spheres were fabricated by means of Ti powders dissolved into HF solution following hydrothermal reaction with ammonia for the first time. The obtained TiO 2 spheres had a good anatase structure and were composed of lots of nanoparticles and nanosheets. These hierarchical TiO 2 spheres exhibited a high surface area and a large light harvesting efficiency. The photocatalytic activity of the hierarchical TiO 2 spheres was determined by degradation of methylene blue in aqueous solution, and was compared to commercial P25 titania. It is revealed that the photocatalytic activity of hierarchical TiO 2 spheres is enhanced a lot. The apparent rate constant of the hierarchical TiO 2 spheres is as 1.5 times as that of P25 titania.