Enhanced visible-light Z-scheme photocatalytic degradation of amoxicillin, chlorpyrifos, and methylene blue by Bi₂O₃/g-C₃N₄/ZnO nanocomposite

In contemporary environmental remediation, photocatalysis is a leading method for degrading organic pollutants under visible light. This study synthesized a novel Z-scheme Bi₂O₃/g-C₃N₄/ZnO nanocomposite using Carbon nitride (g-C₃N₄), Zinc oxide (ZnO), and Bismuth oxide (Bi₂O₃) via wet impregnation, and evaluated its photocatalytic degradation efficacy on organic pollutants such as Amoxicillin (AMX), Chlorpyrifos (CPF), and Methylene blue (MB) under visible light in aqueous medium. Characterization by XRD, HR-SEM, TEM, XPS, UV-DRS, BET, and EIS confirmed the nanocomposite’s structure and properties. The photocatalyst showed a bandgap of 2.1 eV and achieved the degradation efficiencies of 88.6% for MB, 75.0% for CPF, and 62.1% for AMX in 90 min, than that of individual components. Radical trapping experiments identified h⁺ and ⋅O²⁻ as key active species. The synthesized photocatalyst showed remarkable stability and favorable chemical properties over three cycles, proving its effectiveness in the degradation of organic pollutants under aquatic environments.