Photodegradation of methylene blue of niobium-doped zinc oxide thin films produced by electrostatic spray deposition

Nanocrystalline transparent ZnO thin films, with different concentrations of niobium (Nb similar to 0, 5, 10, 15 atoms per formula unit, at%), were successfully deposited by the electrostatic spray deposition method. The crystalline phase, surface morphology, surface roughness and photocatalytic properties of these Nb:ZnO thin films were characterized by X-ray diffraction, scanning electron microscopy, atomic force microscopy, and UV-visible spectroscopy, respectively. The Nb-doped films were tested for their photocatalytic abilities in aqueous solutions of methylene blue (MB) under UV illumination, where it showed that increasing Nb up to 10 at%, with respect to ZnO, enhanced the photocatalytic activity. ZnO films doped with 10 at% Nb demonstrated excellent photocatalytic activity, with degradation of MB achieved in fewer than 2 h of UV irradiation. (c) 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved.