Synthesis, characterization and optical properties of nanostructured ZnWO 4

The ZnWO4 nanorods were fabricated by template-free hydrothermal route and characterized by X-ray diffraction, scanning electron microscopy, Raman, fluorescence and UV–visible spectra. The ZnWO4 nanorods were descended from ZnWO4 nanosheets with the increase of the pH value. The correlations among these optical spectra were studied and the results showed that the ZnWO4 nanorods had good crystallinity and few oxygen-vacancy defects comparing with ZnWO4 nanosheets. Fluorescence emission and UV–visible transmission spectra of ZnWO4 nanorods were increased, while the fluorescence excitation and UV absorption spectra were decreased in the wavelength region of 250–325nm. This phenomenon was reversed in the wavelength region of 325–400nm. The ZnWO4 nanorods displaying superior photocatalytic activity were suitable to be photocatalytic materials which could absorb selectively ultraviolet in the wavelength of 325–400nm for their low recombination probability of light excited electron–hole.