Facile Synthesis and Photocatalysis of Size-Distributed TiO2 Hollow Spheres Consisting of {116} Plane-Oriented Nanocrystallites

TiO2 hollow spheres consisting of highly active {116} plane-oriented crystallites have been synthesized with a wide diameter distribution from 20 nm to over 5 mu m via a facile emulsion method. The prepared hollow spheres possess large specific surface area (S-BET = 104 m(2)/g) and mesopores (15.7 nm), which could be further modified by Pt doping. The mechanisms for hollow sphere formation and {116} plane orientation are discussed briefly. Moreover, compared with normal TiO2 hollow spheres, which usually exhibit uniform diameter distributions and no specific plane orientation, the typical TiO2 hollow spheres with and without Pt doping exhibit good photocatalytic activities for phenol degradation under visible and UV light irradiation. The wide diameter (i.e., curvature) distribution, high specific surface area, conduciveness to forming mesoporous structures, and exposed high-energy surfaces allow good molecular infiltration and adsorption as well as photoelectroactivity and make them attractive for light harvesting.