Enhanced photocatalytic activity of Fe-doped Bi₄O₅Br₂ nanosheets decorated with Au nanoparticles for pollutants removal

The two key factors such as light adsorption and separation of charge carriers in photocatalysts play crucial roles in determining the overall photocatalytic efficiency. Herein, we report synergetic effects of Fe-doping and Au nanoparticles (Au-NPs) deposition on the photocatalytic activity of the modified Bi₄O₅Br₂ (BOB) nanosheets photocatalyst for Bisphenol A degradation and gaseous NO oxidative removal. Fe-doped BOB nanosheets decorated with Au-NPs are synthesized by a two-step chemical method. It was found that the Fe-doped BOB sample decorated with Au-NPs (Au-Fe-BOB) exhibits higher photocatalytic activity than the BOB, Fe-doped BOB, and Au-NPs-loaded BOB samples. Internal Fe-doping in the BOB enhanced the visible light absorption and the separation efficiency of photogenerated charge carriers acting as a scavenger. Moreover, the decorated Au-NPs in the composite photocatalyst extended the light adsorption in the range of visible and near- infrared light due to surface plasmon resonance effect of Au-NPs. The spin trapping measurements of Au-Fe-BOB composite photocatalyst show that the •O₂ ⁻ is a main reactive species during the photocatalytic reaction under visible-light irradiation. The excellent photocatalytic efficiency and stability of Au-Fe-BOB with visible-light response allow to be readily constructed and applied for practical removal of various pollutants using solar light in the future.