Microwave-Assisted Hydrothermal Preparation, Characterization and Photocatalytic Properties of a Chrysanthemum-Shaped ZnWO4 Photocatalyst

A novel chrysanthemum-shaped monocline ZnWO 4 photocatalyst was synthesized by microwave-assisted hydrothermal method with Na 2 WO 4 ·2H 2 O and Zn(NO 3 ) 2 ·6H 2 O as raw materials at different reaction temperatures. The prepared ZnWO 4 photocatalysts were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Field emission scanning electron microscopy (FE-SEM), Transmission electron microscopy, Photoluminescence spectrum (PL) and UV–Vis absorption spectrum (UV–Vis). The photocatalytic property of the prepared chrysanthemum-shaped monocline ZnWO 4 photocatalyst was evaluated by the degradation of Rhodamine B (RhB) in aqueous solution. The effects of reaction temperature on the photocatalytic degradation efficiency of RhB were investigated. The results indicated that the chrysanthemum-shaped monocline ZnWO 4 photocatalyst is prepared by foliated powders with the sizes of about 30 nm and 500 nm respectively at 160 and 220 °C. The PL relative intensity of prepared ZnWO 4 photocatalyst is apparently intensifying with increasing temperature. The photocatalytic property decreases with the increasing recombination probability of the excited electrons and holes. The chrysanthemum-shaped monocline ZnWO 4 photocatalyst prepared at 160 °C possesses the best photocatalytic property, and the degradation efficiency of RhB at 180 min UV-light irradiation is achieved 75 %. The ZnWO 4 has good reusability property on degradation of RhB and the degradation rate is still higher than 65 % after three cycles.