Iron-Doped Bismuth Tungstate with an Excellent Photocatalytic Performance

The metal-doping of Bi-based oxide photocatalysts to enhance the photocatalytic performance has been a research hotspot in recent years, but the research on the mechanism of doping-induced photoactivity improvement is still incomplete. To illustrate the mechanism completely and clearly, Fe-doped Bi2WO6, as an example, was synthesized by a facile hydrothermal route. Fe-doped Bi2WO6 exhibits a much higher photoactivity than pure Bi2WO6 in the degradation of RhodamineB (RhB) and salicylic acid (SA). By replacing W6+, the Fe3+ doping narrows the energy band gap and generates many oxygen vacancies, which can increase the adsorption of both RhB and SA, and the introduced defect and Fe-doping energy levels in the band gap of Bi2WO6 increase the separation efficiency of photoinduced charge carriers significantly. These lead to the considerable photoactivity enhancement of Fe-doped Bi2WO6. The photoactivity of Fe-doped Bi2WO6 is stable and superior to that of most reported modified Bi2WO6 photocatalysts. This work illustrates in detail the mechanism for the photoactivity improvement of Fe-doped Bi2WO6, which benefits the research of other metal-doped photocatalysts.