Effect of surfactant on the photocatalytic activity of Bi₂WO₆ nanoparticles

Abstract

A series of Bi₂WO₆ photocatalysts were synthesized by a surfactant-assisted hydrothermal method. The products were characterized with X-ray diffraction (XRD), UV–vis-near-IR diffuse reflectance spectra (UV–Vis), scanning electron microscope (SEM) and Brunauer-Emmett-Teller (BET) surface area measurement. XRD results showed that the Bi₂WO₆ samples possessed pure monoclinic phase. The surfactant, especially SDBS addition would greatly affect the physical and chemical properties of Bi₂WO₆. The average crystalline size of BWO-SBDS is rather smaller than that of BWO-None photocatalyst. The UV–Vis and BET results indicated that the BWO-SBDS has a narrower band gap energy and a larger surface area than BWO-CTAB and BWO-None products. The photocatalytic activities of as-prepared samples were evaluated by the degradation of methylene blue (MB) in an aqueous solution. The SDBS-assisted Bi₂WO₆ product had a much higher photocatalytic activity than the other two Bi₂WO₆ products in our photocatalytic system. The degradation percentage was about 97.0% with the reaction time at 120 min for BWO-SBDS sample. The improvement reason by SDBS adding was also discussed.