Photocatalytic enhancement of n-p-n ternary heterostructure of BiVO4/rGO/BiOBr for RhB degradation under visible light irradiation

Herein, the ternary phase of n-type BiVO4/p-rGO/n- BiOBr (3%rGO/1V2Br) was synthesized by one-pot hydrothermal method and firstly evaluated for its potential application in photocatalysis. The 3 %rGO/1V2Br shows the highest photocatalytic efficiency of 100 % compared to that of the binary BiVO4/BiOBr (1V2Br), single BiVO4, and BiOBr phases of 87 %, 25 %, and 55 % respectively. Scanning electron microscope and X-ray diffraction results suggest successful preparation of the ternary BiVO4/rGO/BiOBr phase and close contacts among the three components. Chemical interactions at heterointerface, supported by new V-C bond formation and binding energy shift from X-ray photoelectron spectroscopy study, could facilitate charge transfer and promote charge separation as evidenced by photoluminescence and photoelectrochemical studies. Photocatalytic mechanism and energy band alignment are proposed based on Mott-Schottky, UV–vis diffuse reflectance, and scavenger trapping experiments.