Synthesis, characterization and optical properties of nanostructured ZnWO4

•ZnWO4 nanorods and sheets are fabricated by one pot hydrothermal method.•pH value plays an important role in ZnWO4 nanorods formation.•Correlations between optical properties and catalytic activity are studied.•ZnWO4 nanorods have selectivity to absorb given ultraviolet.•ZnWO4 nanorods as catalytic with low electron–hole recombination probability.

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.