Anatase TiO2 nanoparticles immobilized on ZnO tetrapods as a highly efficient and easily recyclable photocatalyst

Anatase TiO2 nanoparticles in the size of ca. 6 nm were immobilized on the single-crystalline tetrapod-like ZnO (denoted as T-ZnO in the text) with dimensions up to 20-50 mu m by vapor hydrolysis method (VHM). Compared to the wet chemical deposition method, more uniform TiO2 layers with a tunable thickness were achieved by VHM. T-ZnO showed a relatively low efficiency in the photooxidation reaction of phenol. After coating of anatase nanoparticles, the photocatalytic activity of the nanocomposite (TiO2/T-ZnO) was significantly enhanced in photooxidation of phenol. Moreover, in contrast to the discrete nanoparticles, TiO2/T-ZnO could be very easily recovered from the treated solution by a most common filter paper. The easily recyclable feature and the high efficiency made TiO2/T-ZnO act as low-cost and feasible photocatalysts for the large-scale applications. (C) 2007 Elsevier B.V. All rights reserved.