Enhanced Photocatalytic Activity of ZnWO4/BiOI Composites Under Visible-Light Irradiation

In this work, ZnWO4/BiOI composite photocatalysts were synthesized via a facile water bath method. The photocatalysts were characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Vis diffusion reflectance spectroscopy (DRS) and photoluminescence (PL) spectroscopy. Furthermore, the photocatalytic degradation of methylene blue (MB) using ZnWO4/BiOI was studied under the irradiation of visible-light. The results showed that ZnWO4/BiOI composites displayed much higher photocatalytic activity than pure ZnWO4 and BiOI. Among all the samples, ZnWO4/BiOI with the molar ratio of 5: 5 (ZB-5) displayed the highest photocatalytic activity. The Enhancement of the photocatalytic activity primarily resulted from the effective separation of photogenerated electron-hole pairs. According to the radical scavengers experiments, O-center dot(2)- and h(+) played an important role during the degradation process.