Synthesis, characterization and optical properties of nanostructured ZnWO₄

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 250-325 nm. This phenomenon was reversed in the wavelength region of 325-400 nm. The ZnWO₄ 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.