Phase control of hierarchically structured mesoporous anatase TiO2 microspheres covered with {001} facets

The controlled synthesis of anatase titanium dioxide (TiO2) with both high surface area and high energy facets is technologically important for its application in photocatalysis, photoelectrochemical cells, and solar cells. Here we report a simple and fluorine free hydrothermal method to synthesize hierarchically nanostructured mesoporous anatase TiO2 spheres (MATS), which were covered with {001} facets. Mild H2SO4 was used as both a phase-inducer for the formation of the anatase phase and a capping agent to promote oriented growth and formation of {001} facets. Detailed XRD and SEM studies suggested that formation of MATS follows a typical nucleation and growth process. The refining or reconstruction of TiO2 crystal structure during growth resulted in a mesoporous crystalline framework that exhibits enhanced adsorption and photocatalytic degradation of rhodamine B in comparison with that of commercial Degussa P25 TiO2.