Fabrication and enhanced visible-light photocatalytic activities of BiVO4/Bi2WO6 composites

BiVO4/Bi2WO6 composite photocatalysts were synthesized by coupling a homogeneous precipitation method with hydrothermal techniques. The as-prepared samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), UV-Vis diffusion absorption spectroscopy (DRS) and photoluminescence (PL), respectively. The photocatalytic activities were evaluated by the degradation of methyl blue (MB) under visible-light irradiation. The results reveal that BiVO4/Bi2WO6 composites exhibit higher photocatalytic activities than either pure Bi2WO6 or BiVO4. The 0.3BiVO(4):0.7Bi(2)WO(6) sample shows the best photocatalytic performance. The enhancement of photocatalytic activity is attributed to the improvement of light absorption, the excellent adsorbability, the narrow band gap and increasing separation rate of photo-generated charge carriers. The possible photocatalytic mechanism is discussed on the basis of the band structures of BiVO4 and Bi2WO6.