Synthesis of Ag₃PO₄/Ag₄P₂O₇ by microwave-hydrothermal method for enhanced UV-visible photocatalytic performance

Ag₃PO₄/Ag₄P₂O₇ photocatalysts were successfully synthesized by microwave-hydrothermal method. Tuning the properties of photocatalysts was achieved using different amount of acetic acid (CH₃COOH) and sodium hydroxide (NaOH) to adjust pH value of precursor solution (pH = 4, 7, 10 and 12). The crystal structure, morphology and optical property of samples were characterized and explained. The photocatalytic activity of sample was determined by degradation of rhodamine B (RhB) and methyl orange (MO) under a wavelength range of 350-700 nm irradiation. The results demonstrated that the change in shape of particles was not observed whereas the average particle size was decreased with increasing pH value because of the high hydroxide ions (OH^-). The sample synthesized in the solution with the pH of 10 exhibited excellent photocatalytic performance and stability because of the highest surface area and the present of Ag₄P₂O₇ on the surface of particles. The highest photodegradation efficiency was 99.34 and 96.12% by degrading RhB and MO, respectively. The enhancement of photocatalytic performance of Ag₃PO₄/Ag₄P₂O₇ was discussed. The active species trapping experiments showed that the h⁺ was the main active species to decompose the dye molecules.