Mechanochemical synthesis of nanocrystalline ZnWO4 at room temperature

Single nanocrystalline ZnWO4 powders were successfully synthesized by ball milling at room temperature. A stoichiometric mixture of ZnO and WO3 in a 1:1 molar ratio was subjected to intense mechanical treatment in air using a planetary ball mill (Fritsch – Premium line – Pulversette No. 7) for a period varying from 5 to 300 min. The influence of the four different milling conditions was investigated on the formation of ZnWO4. The products obtained were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Brunauer–Emmer–Teller (BET) surface area, infrared (IR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The synthesis of ZnWO4 powder started after 5 min milling time and finished after 30 min milling time at a higher speed (1000 rpm). The mechanical treatment up to 300 min did not lead to phase and structure change of ZnWO4. The product obtained contained nanoparticles with a size of about 50 nm. The photocatalytic activity of the ZnWO4 powders obtained was investigated by degradation of a model aqueous solution of Malachite Green (MG) upon UV-light irradiation.

Research highlights▶ The ZnWO4 nanoparticles were obtained after 30 min milling time at room temperature. ▶ The milling speed is decisive factor for the rapid synthesis of ZnWO4. ▶ The obtained nanocrystalline ZnWO4 powders exhibit a photocatalytic activity.