Synthesis of Ag3PO4/G-C3N4 Composite with Enhanced Photocatalytic Performance for the Photodegradation of Diclofenac under Visible Light Irradiation

A new visible-light-driven heterojunction Ag3PO4/g-C3N4 was prepared by a simple deposition-precipitation method for the degradation analysis of diclofenac (DCF), a model drug component, under visible-light irradiation. The heterojunction photocatalysts were characterized by a suite of tools. The results revealed that the introduction of Ag3PO4 on the surface of g-C3N4 greatly promoted its stability and light absorption performance. In addition, the effects of the heterojunction mixing ratios were studied, when the molar ratio of Ag3PO4 to g-C3N4 in the composite was 30%, the as-prepared photocatalyst Ag3PO4/g-C3N4 (30%) possessed the best photocatalytic activity toward the photodegradation of DCF, and the optimal photocatalyst showed a DCF degradation rate of 0.453 min−1, which was almost 34.8 and 6.4 times higher than those of pure g-C3N4 (0.013 min−1) and Ag3PO4 (0.071 min−1) under visible light irradiation (λ ≥ 400 nm). The trapping experimental results showed that h+, ·OH, and ·O2 were the main reactive oxygen species during the photocatalytic reaction. The improved performance of the composites was induced by the high charge separation efficiency of the photogeneration electron-hole pairs as well as the surface plasmon resonance (SPR) endowed in the Ag0 nanoparticles, and ultimately enhanced the DCF photodegradation.