Synthesis, characterization and optical properties of nanostructured ZnWO4

The ZnWO 4 nanorods were fabricated by template-free hydrothermal route and characterized by X-ray diffraction, scanning electron microscopy, Raman, fluorescence and UV–visible spectra. The ZnWO 4 nanorods were descended from ZnWO 4 nanosheets with the increase of the pH value. The correlations among these optical spectra were studied and the results showed that the ZnWO 4 nanorods had good crystallinity and few oxygen-vacancy defects comparing with ZnWO 4 nanosheets. Fluorescence emission and UV–visible transmission spectra of ZnWO 4 nanorods were increased, while the fluorescence excitation and UV absorption spectra were decreased in the wavelength region of 250–325   nm. This phenomenon was reversed in the wavelength region of 325–400   nm. The ZnWO 4 nanorods displaying superior photocatalytic activity were suitable to be photocatalytic materials which could absorb selectively ultraviolet in the wavelength of 325–400   nm for their low recombination probability of light excited electron–hole.