A novel dual-Z-scheme g-C₃N₄/BiOCl/Ag₂WO₄ heterojunction engineered for sunlight-driven photocatalytic degradation of methylene blue and amoxicillin

Abstract

International audienceThis paper investigates the synthesis of g-C3N4/BiOCl/Ag2WO4 nanocomposites for application in solar energy-driven photodegradation of Methylene Blue dye (MB) and Amoxicillin antibiotic (AMOX). The as-prepared precursor photocatalysts (Ag2WO4, BiOCl, and g-C3N4) and nanocomposite photocatalyst g-C3N4/BiOCl/Ag2WO4 were investigated using a full characterization process to determine their oxidation states (XPS), composition (EDX), morphology (SEM & TEM), structure (FTIR), and crystallinity (XRD). Examination of these characteristics attests to successful synthesis of g-C3N4/BiOCl/Ag2WO4 nanoparticles with enhanced crystallinity. Photocatalysis experiments proved that ternary nanocomposite is highly active towards degrading contaminating molecules, with 98 % for MB and 95 % for AMOX, through redox processes driven by sunlight. Monte Carlo simulation studies reveal that the g-C3N4/BiOCl/Ag2WO4 composite is readily formed, and MB molecules are adsorbed onto its surface in multiple layers, driven by favorable negative adsorption energies.In addition, the recyclability of g-C3N4/BiOCl/Ag2WO4 demonstrates its ability to retain photocatalytic activity across four consecutive cycles. According to active species trapping experiment and UV–vis diffuse reflectance spectroscopy (DRS), a proposed photocatalytic mechanism elucidates the observed enhancement in performance of the g-C3N4/BiOCl/Ag2WO4 system. According to the mechanism, the newly designed dual Z-scheme heterojunction, which promotes the synergistic interaction among the photocatalysts, further accelerates the effective separation and transfer of e−/h+ and accordingly greatly improves the photocatalytic degradation efficiency