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

A novel TiO 2-x /Ag 3 PO 4 composite photocatalyst with controllable oxygen vacancies (V o ·) amount was designedly prepared to avoid the photocorrosion and promote reduction capacity of Ag 3 PO 4 photocatalyst. The V o · on TiO 2-x work as molecular oxygen activation center trapping electron and O 2 to form ·O 2 - , and then avoided the electrons combine with h + and/or Ag + . Compared with Ag 3 PO 4 , TiO 2-x , and TiO 2 /Ag 3 PO 4 , TiO 2-x /Ag 3 PO 4 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-·O 2 - species spectra revealed that the TiO 2-x /Ag 3 PO 4 had a higher photocurrent density, lower photocorrosion and more generation of superoxide radical than those of Ag 3 PO 4 . Interestingly, compare with single h + degradation pathway over Ag 3 PO 4 , the h + and ·O 2 - synergistic degradation pathway over TiO 2-x /Ag 3 PO 4 is more beneficial to the BPA degradation. This work highlights the relations between the photocatalyst structure, active species and pollutant degradation pathway.