Hydrogen peroxide assisted rapid synthesis of TiO2 hollow microspheres with enhanced photocatalytic activity

Anatase TiO2 hollow microspheres (TiO2-HMSs) have attracted great attention owing to their versatile applications including photocatalysis, sensing, lithium-ion batteries, drug-delivery carrier and solar energy conversion. However, the synthetic procedures for TiO2-HMSs are complex and/or time-consuming. In this paper, rapid synthesis of TiO2-HMSs in the presence of H2O2 (0-4.4 mol) was systematically studied by hydrothermal treatment of the mixed solution of (NH4)(2)TiF6 (6 mmol) and (NH4)(2)CO (40 mmol). It was found that the diameters of the obtained spherical TiO2 aggregates decreases with increase in the amount of H2O2, and H2O2 not only promotes the crystallization of primary anatase TiO2 nanocrystals, but also induces the hollowing process of TiO2 microspheres. The prepared TiO2-HMSs shows high photocatalytic activity in degradation of Brilliant Red X-3B, an anionic dye, under UV irradiation due to H2O2-mediated enhanced crystallization and improved adsorption. A proposed formation mechanism was put forward for the rapid formation of TiO2-HMSs based on H2O2-assisted nucleation, and followed by fluoride-induced self-transformation (FIST). (C) 2013 Elsevier B.V. All rights reserved.