Annealing Effect of ZnO Seed Layer on Enhancing Photocatalytic Activity of ZnO/TiO_2 Nanostructure

摘要

Zinc oxide (ZnO)/titanium dioxide (TiO_2) nanorods have been synthesized via a hydrothermal method for ZnO nanorods and an electron-beam deposition for TiO_2 nanorods. This work examined the effect of annealing ZnO seed layer on the photocatalytic activity of the ZnO/TiO_2 nanorods which was determined from photodecomposition of methylene blue under UV irradiation. The photocatalytic activity of the ZnO/TiO_2 nanorods was improved with increasing annealing temperature of the seed layer from 300℃ to 500℃. Annealing the seed layer at 500℃ showed the best photocatalytic activity resulting from high UV absorption ability, a large surface area with flower structure and copious oxygen defects which promote separation of electron-hole pairs reducing electron recombination. The prepared nanorods were characterized by field emission-scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), photoluminescence (PL), and UV-visible spectroscopy.