Hydrothermal synthesis of series Cu-doped Bi2WO6 and its application in photo-degradative removal of phenol in wastewater with enhanced efficiency

To develop highly efficient photocatalyst for treatment of phenol-contained wastewater, Cu-doped Bi2WO6 (Cu-Bi2WO6) photocatalyst is synthesized via an optimized hydrothermal method. The influences of the synthesis parameters such as Cu loading, initial pH, reaction time and temperature on the crystal structure of Cu-Bi2WO6 are systematically examined from XRD, XPS, DRS and SEM analyses. The results show Cu doping leads to a significant red-shift of the absorption band of Cu-Bi2WO6 in visible light region. When Cu loading is 0.5 wt%, Cu-Bi2WO6 shows sharp diffractions due to higher crystallinity, and further for pH = 0.6, the prepared Cu-Bi2WO6 shows a narrow diffraction with greater intensity. Further analyses show that Cu-Bi2WO6 is characterized by a 3D flower spherical morphology expressing a relatively large micro-porosity size, with specific surface area as high as 85 m2/g. The photocatalytic activity of Cu-Bi2WO6 for degradation of phenol in wastewater under visible light irradiation is systematically examined. The related kinetic study shows that Cu doping can greatly improve the photocatalytic activity of the resulting Cu-Bi2WO6, and moreover Cu loading has a great impact on the photocatalytic activity. Optimally, Cu-Bi2WO6 doped with 0.5 wt% Cu exhibits the highest photocatalytic activity with the efficiency for phenol removal as high as 92%, 23% higher than that of pristine Bi2WO6 under the same condition. Our work provides a facile, cost-effective and environmentally friendly way to enhance the efficiency of Bi2WO6 for photo-catalytically degradative removal of phenol pollutants in wastewater.