Zinc-containing precursor dependence of hydrothermal method for the synthesis of N-doped ZnO photocatalysts

Abstract

N-doped ZnO photocatalysts with enhanced UVA-light and visible-light-driven activities were prepared by hydrothermal treatment of various zinc-containing precursors, including zinc oxide, zinc hydroxide and zinc nitrate, with urea as a doping agent. The influences of zinc-containing precursors used in hydrothermal process on the crystal structure, morphology, surface functional groups and optical properties of N-doped ZnO catalysts were investigated by XRD, SEM, FTIR, Raman and UV-visible diffuse reflectance spectra, respectively. Their photocatalytic activity was evaluated via the degradation of methylene blue. According to the results, zinc hydroxide was found to be the most appropriate precursor for the synthesis of N-doped ZnO. The best photocatalytic performance of this catalyst under both UVA and visible light illumination can be attributed to the increase of surface hydroxyl groups, the formation of surface oxygen defects and surface Zn-N bonds as well as the reduction of particle size and the production of rod-like particles.