TiO2-x/Ag3PO4 photocatalyst: Oxygen vacancy dependent visible light photocatalytic performance and BPA degradative pathway

A novel TiO2-x/Ag3PO4 composite photocatalyst with controllable oxygen vacancies (V-o center dot) amount was designedly prepared to avoid the photocorrosion and promote reduction capacity of Ag3PO4 photocatalyst. The V-o center dot on TiO2-x work as molecular oxygen activation center trapping electron and O-2 to form center dot O-2-, and then avoided the electrons combine with h(+) and/or Ag+. Compared with Ag3PO4, TiO2-x, and TiO2/Ag3PO4, TiO2-x/Ag3PO4 showed obviously efficient visible light and natural indoor weak light photocatalytic activity and stability for the photodegradation of Bisphenol A (BPA). The photoelectric conversion spectra, Ag 3d XPS narrow scan spectra, ESR DMPO-center dot O-2- species spectra revealed that the TiO2-x/Ag3PO4 had a higher photocurrent density, lower photocorrosion and more generation of superoxide radical than those of Ag3PO4. Interestingly, compare with single h(+) degradation pathway over Ag3PO4, the h(+) and center dot O-2- synergistic degradation pathway over TiO2-x/Ag3PO4 is more beneficial to the BPA degradation. This work highlights the relations between the photocatalyst structure, active species and pollutant degradation pathway.