One-step template-free fabrication of mesoporous ZnO/TiO2 hollow microspheres with enhanced photocatalytic activity

Mesoporous ZnO/TiO2 hollow microspheres have been successfully synthesized by a facile one-step hydrothermal route without any template. The effect of reactants, temperature and hydrothermal time on the morphology and photocatalytic degradation activity has been investigated in details. The hollow microspheres with average diameter of 0.5-2 mu m showed time-dependent growth process and consisted of nanoparticles with a diameter of 10-20 nm. The photocatalytic activity of ZnO/TiO2 hollow microspheres was evaluated via the photocatalytic degradation of methyl orange (MO). Compared with the pristine TiO2 hollow microspheres or ZnO nanosheets, the ZnO/TiO2 hollow microspheres produced significantly positive effect on the band-gap energy shift (from 3.16 eV (TiO2 ) to 2.80 eV (ZnO/TiO2 )) and photocatalytic degradation (with a high apparent reaction rate of 10.19 10(-2) min(-1)) probably owing to the hybrid hollow microsphere morphology and their synergistic catalytic effect. (C) 2014 Elsevier B.V. All rights reserved.