Fabrication and Photocatalysis of Rod-like ZnWO4 Nanocrystallites

The Wolframite ZnWO4 nanocrystallites were prepared by a facile, template-free microwave hydrothermal method using Na2WO4·2H2O and Zn(COOCH3)2·2H2O as starting materials. The phase, morphology and optical properties of as-prepared samples were characterized by X-ray Diffraction (XRD), Transmission Electron Microscope (TEM), UV-Vis absorption spectra (UV-Vis) and photoluminescence spectroscopy (PL). Results indicate that ZnWO4 nanocrystallites have a preferential orientation growth along the (100) planes, and the morphology of ZnWO4 nanocrystallites change into rodlike structure with the increase of microwave hydrothermal time. An intense blue PL emission with a 460 nm wavelength is observed when the as-prepared ZnWO4 nanocrystallites are excited by a 295 nm wavelength, and they show a strong absorption in the ultraviolet region. The ZnWO4 nanocrystallites whose orientation degree of (100) planes is 0.24 with the particle sizes of 50–60 nm show the best photocatalytic properties.