Influence of defects on the photocatalytic activity of Niobium-doped ZnO nanoparticles

摘要

Niobium (Nb)-doped zinc oxide nanoparticles have been prepared by a simple sol-gel method. The structural, optical and photocatalytic activity of Nb-doped ZnO nanoparticles have been systematically investigated as a function of Nb~(5+) concentration. The photocatalytic activity of Nb-doped ZnO nanoparticles has been studied by methylene blue dye degradation under UV irradiation. Nb-doped ZnO nanoparticles exhibit better photocatalytic activity compared to undoped ZnO nanoparticles. The UV light induced photo catalytic activity of 2% Nb-doped ZnO is found to be twice that of undoped ZnO. The influence of bulk defects on the photocatalytic activity has also been investigated. At higher Nb. concentrations, bulk defects such as zinc vacancy, V_(Zn) decreased the photocatalytic activity of Nb-doped ZnO nanoparticles. Results obtained from Photoluminescent spectra and magnetic measurements of such systems have been combined to establish the defect mediated mechanism of photocatalytic degradation.