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

Pb₉(PO ₄)₆/Ag₃PO ₄ photocatalysts with different amounts of Pb₉(PO ₄)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 Pb₉(PO ₄)₆/Ag₃PO ₄ photocatalysts show much higher photocatalytic activities than pure Ag₃PO ₄ under visible light irradiation in the methyl‐orange (MO ) decomposition. Especially, the 3.0 wt% Pb₉(PO ₄)₆/Ag₃PO ₄ 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 Pb₉(PO ₄)₆/Ag₃PO ₄ is closely related to , the main active oxygen species.