Effect of Sintering Temperature on the Photocatalytic Activity of Flower-Like Bi2WO6

Bi2WO6 is reportedly active for the photocatalytic degradation of organic compounds in aerated aqueous solution, but factors influencing the photocatalytic activity of pristine Bi2WO6 have received little attention. In this study, the effect of sintering temperature on the physical properties of flower-like Bi2WO6 was investigated. The catalyst was synthesized through the hydrothermal reaction of Na2WO4 and Bi(NO3)3 at 160 for 20 h, followed by sintering in air at different temperatures for 3 h. Bi2WO6 samples were characterized with X-ray diffraction, scanning electron microscopy, and Raman, ultraviolet-visible diffuse reflectance, and photoluminescence spectroscopies. All samples had similar phase compositions and electronic structures. Samples exhibited different activities for the photocatalytic degradation of phenol in aerated aqueous solution, under ultraviolet light. With increasing Bi2WO6 sintering temperature, the rate of phenol degradation first increased and then decreased. The maximum rate of phenol degradation was observed from the catalyst sintered at 350 . Similar results were obtained when the rate of phenol degradation was normalized with the specific surface area of the catalyst, as determined by N2 adsorption. The observed sintering temperature-dependent photoactivity of Bi2WO6 was attributed to a combination of its crystallinity, light absorption, and surface defects.