Synthesis of Tin-Doped Three-Dimensional Flower-like Bismuth Tungstate with Enhanced Photocatalytic Activity

Photocatalytic degradation of harmful organic matter is a feasible and environmentally friendly method. Bi₂WO₆ has become a hotspot of photocatalysts because of its unique layered structure and visible light response. In the present study, Sn doping was adopted to modified Bi₂WO₆ by hydrothermal method. The Sn-doped Bi₂WO₆ photocatalysts were characterized by XRD, SEM, TEM, BET, XPS, PL, and DRS, respectively. The results show that Sn-doped Bi₂WO₆ shows three-dimensional (3D) flower-like morphology, which is composed of two-dimensional (2D) nanosheets. Sn⁴⁺ ions enter into the Bi₂WO₆ lattice, producing a degree of Bi₂WO₆ lattice distortion, which is in favor of reducing the recombination of photogenerated electrons and holes. Moreover, the specific surface area of Bi₂WO₆ is significantly increased after doping, which is beneficial to providing more active sites. The photocatalytic results show that 2%Sn-Bi₂WO₆ exhibits the highest photocatalytic activity. After 60 min of irradiation, the photocatalytic degradation degree of methylene blue (MB) increases from 80.6% for pure Bi₂WO₆ to 92.0% for 2%Sn-Bi₂WO₆. The first-order reaction rate constant of 2%Sn-Bi₂WO₆ is 0.030 min^-1, which is 1.7 times than that of pure Bi₂WO₆.