Fabrication of Novel Double Z-Scheme Photocatalyst WO3-Ag3PO4-Bi2WO6 with Excellent Visible Photocatalytic Activity

A novel ternary Z-scheme photocatalytic system containing Ag3PO4, WO3 and Bi2WO6 was prepared by a one-pot hydrothermal method. The WO3-Ag3PO4-Bi2WO6 photocatalyst was characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis diffuse reflection spectroscopy (DRS). Using Rhodamine B (RhB) as the target of elimination, WO3-Ag3PO4-Bi2WO6 exhibited outstanding photocatalytic compared with those of Bi2WO6 and WO3-Bi2WO6. The rate constants of photocatalytic degradation of RhB for WO3-Ag3PO4-Bi2WO6 (0.2:0.3:1) was 1.9 and 1.3 times that of pure Bi2WO6 and WO3-Bi2WO6. In this system, the efficient separation and migration of the photoinduced current carriers was realized through a double Z-scheme electron-transfer mechanism in which the Ag3PO4 and WO3 acted as electron donor. The Ag3PO4 served as a charge transmission bridge between the WO3 and the Bi2WO6, and the Z-scheme kept the electrons with high reducing capability in the conduction band (CB) of Bi2WO6 and the holes with high oxidation capability in the valence band (VB) of WO3, thereby enhancing the photocatalytic activity and stability of Ag3PO4. The present study provided a new perspective for enhancing photocatalytic and anti-photocorrosion performances in perishable photocatalysts for organic sewage and other environmental contamination treatments