Ternary Au/Bi2WO6/BiOBr composites with synergistic effect for enhanced photocatalytic activity

Ternary Au/Bi2WO6/BiOBr composites were skillfully prepared via a two-step synthetic route. The two-component Bi2WO6/BiOBr heterojunction was firstly fabricated by hydrothermal method, and Au nanoparticles (NPs) were further introduced and uniformly anchored on the surface of Bi2WO6/BiOBr, where the loaded Au NPs could be beneficial for improving visible-light absorption and adjusting photoinduced charge carriers in the heterostructure through surface plasmon resonance (SPR). In comparison with pristine Bi2WO6 and two-component Bi2WO6/BiOBr, the ternary Au/Bi2WO6/BiOBr composite exhibits a better photocatalytic activity for removal of rhodamine B (RhB) under visible light irradiation. The degradation efficiency of GTB-3 composite 1.9 times higher than that of the pure Bi2WO6 and 1.24 times than that of Bi2WO6/BiOBr. Trapping tests with different scavengers revealed that not hydroxyl radicals but superoxide radicals and photogenerated holes were highly responsible for the degradation process. The enhanced photocatalytic activity was ascribed to the synergetic effect of heterojunction effect (efficient separation of charge carriers), porous structure of Bi2WO6 (strong adsorption), SPR of Au.