Ag-P/g-C3N4, a composite visible light catalyst modified by Ag-P, was synthesized via the thermal polymerization among melamine, diammonium hydrogen phosphate and silver nitrate. The yielded catalyst was characterized and analyzed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and photoluminescence spectroscopy (PL). The visible light catalytic activity was systematically measured in visible light-triggered degradation experiments of methylene blue The results showed that the modification of Ag-P composite did not significantly change the crystal structure of g-C3N4, but greatly inhibited the recombination of photogenerated electrons and holes, thus improving its visible light catalytic activity. After 120 min of visible light irradiation, the rate constant of degradation catalyzed by Ag(2%)-P/g-C3N4 reached 0.00816 min-1, which was 2.1 times that by the original g-C3N4 and 1.7 times that by P/g-C3N4. In addition, the visible light catalytic degradation mechanism and recycling stability of Ag-P/g-C3N4 were explored. |