Synthesis of Pb9(PO4)6/Ag3PO4 Composite Photocatalysts with Enhanced Visible Light Photocatalytic Activity

Pb-9(PO4)(6)/Ag3PO4 photocatalysts with different amounts of Pb-9(PO4)(6) were successfully synthesised by the ion exchange method. The catalysts were characterized by X-ray diffractometry (XRD), High-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), Brunauer- Emmett-Teller (BET), Fourier transform infrared spectrometry (FT-IS), and ultraviolet-visible (UV-vis) spectroscopy. All Pb-9(PO4)(6)/Ag3PO4 photocatalysts show much higher photocatalytic activities than pure Ag3PO4 under visible light irradiation in the methyl-orange (MO) decomposition. Especially, the 3.0wt% Pb-9(PO4)(6)/Ag3PO4 photocatalyst shows the highest photoactivity and also high stability after five cycles. The MO degradation rate during each cycle is almost maintained at 97%. Photo-electrochemical measurement of photocatalysts verified that the enhancing photocatalytic activity was resulted from the electron-hole pair high separation. The photocatalytic activity enhancement of Pb-9(PO4)(6)/Ag3PO4 is closely related to <bold>OH</bold>, the main active oxygen species.