Preparation and Photocatalytic Performance of Ag3PO4/g-C3N4/Biochar Composite Materials

As a photocatalyst, silver phosphate (Ag3PO4) features high quantum yield and strong photocatalytic ability, demonstrating great potential in water splitting and the treatment of water pollutants. However, its own photo-corrosion and low solubility in water limit its application. To address these issues, the combination of Ag3PO4 with other semiconductor materials to form composite photocatalysts can enhance its catalytic activity and structural stability, facilitating the photocatalytic degradation of organic pollutants in wastewater. In this work, Ag3PO4/g-C3N4/C composite photocatalytic materials were successfully prepared using biochar (C), g-C3N4, AgNO3, and Na2HPO4·12H2O as raw materials through a co-precipitation method. The Ag3PO4/g-C3N4/C (mass ratio 4:1:0.1) composite photocatalyst exhibited excellent degradation performance for MB and RhB and maintained good stability. During the degradation of MB and RhB, the main active species were h+ (holes), •O2− and •OH. The MB removal efficiency reached 97% in 40 mL of 10 mg/L MB aqueous solution within 60 min of visible light irradiation, and the removal efficiency of RhB reached 96% in 40 mL of 10 mg/L RhB aqueous solution within 80 min of visible light irradiation. After three cycles of reuse, the removal efficiencies of MB and RhB photocatalyzed by Ag3PO4/g-C3N4/C (4:1:0.1) still reached 79% and 74%, respectively. The Ag3PO4/g-C3N4/C composite photocatalyst can be applied to the degradation of organic pigment in the environment dye wastewater, contributing to environmental remediation and the green development of the ecological environment.