The Effects of Solvents on the Solvothermal Synthesis of BiVO<sub>4</sub> Photocatalyst Powders

In this study, the effects of different solvents such as ethanol, ethylene glycol, glycerol on the preparation of BiVO 4 via solvothermal process, and the influent of calcination heat treatment were studied. The crystal structure, surface area, morphology and optical properties of the obtained BiVO 4 particles were investigated by means of X-ray Diffraction (XRD), Brunauer Emmett Teller method (BET), Scanning electron microscope (SEM) and UV-Vis reflectance spectroscopy (UV-Vis DRS), respectively. XRD patterns reveal that all of the obtained BiVO 4 samples prepared by solvothermal at 130°C for 4 h have monoclinic structure. The UV-Vis DRS demonstrates that the band gaps of prepared BiVO 4 are about 2.38-2.40 eV. The photocatalytic activity was evaluated by photo-degradation of rhodamine B (Rh B) solution under visible light irradiation (λ>420 nm). As the results, the BiVO 4 prepared by using ethanol having high crystallinity and surface area showed the highest visible light photocatalytic activity compared to using glycerol and ethylene glycerol, respectively. Furthermore, the photocatalytic activity of BiVO 4 prepared by using ethylene glycerol and glycerol could be enhanced by calcination heat treatment at 500°C for 2 h.