Synthesis and characterization of Ag/Ag₃PO₄ nanomaterial modified BiPO₄ photocatalyst by sonochemical method and its photocatalytic application

Ag/Ag₃PO₄ nanomaterial modified BiPO₄ photocatalysts (Ag/Ag₃PO₄/BiPO₄) were synthesized by sonochemical method. The BiPO₄ and Ag/Ag₃PO₄/BiPO₄ photocatalysts were characterized by XRD, UV–Vis DRS, Raman, and TEM analysis. The photocatalytic activity of the prepared heterostructures was studied through the photodegradation of methylene blue (MB) under visible-light irradiation (λ > 420 nm, 70 W/cm²). The photodegradation of MB was found to be follow pseudo-first-order kinetics. The antimicrobial activity of the prepared heterostructures has also been evaluated in the disinfection of pathogens (Escherichia coli and Staphylococcus aureus). The prepared Ag/Ag₃PO₄/BiPO₄ photocatalysts displayed considerably higher photocatalytic activity (>99% degradation within 25 min and >99% disinfection within 20 min) than did pure BiPO₄. This enhanced photocatalytic activity of the Ag/Ag₃PO₄/BiPO₄ photocatalysts can be attributed to the high separation efficiency and low recombination rate of photogenerated electron–hole pairs, as well as the Ag⁺ ions release under visible light irradiation. The possible mechanism underlying the enhanced photocatalytic activities of the Ag/Ag₃PO₄/BiPO₄ photocatalysts is also provided.