Modulating charge transport behavior across the interface via g-C3N4 surface discrete modified BiOI and Bi2MoO6 for efficient photodegradation of glyphosate

This study successfully synthesized ternary composite photocatalysts g-C3N4/BiOI/Bi2MoO6 (CN/BI/MO) via dispersion modification of BiOI and perovskite-like materials Bi2MoO6 on graphitic carbon nitride (g-C3N4), for effective degradation of glyphosate in pesticide wastewater. Electrochemical measurements showed that the CN/BI/MO ternary composite catalyst presented extremely high photogenerated electron-hole (e-h+) separation efficiency and low e- transfer resistance, which was favorable for prolonging the lifetime of photogenerated charges. In addition, the results of photoluminescence spectroscopy (PL) and UV-vis diffuse reflectance spectroscopy (UV-Vis DRS) showed that CN/BI/MO had a broad response range of visible light and vital light absorption ability. Therefore, the composites exhibited more vigorous photocatalytic activity than the monomers. Among them, 30% CN/BI/MO catalyst had the highest photocatalytic activity, and the photodegradation rate of glyphosate was up to 94% under limited 30 min visible light irradiation. The total organic carbon (TOC) assay results indicated that the ternary photocatalytic system improved the mineralization efficiency of glyphosate. This work provides a potential solution for effectively treating pesticide wastewater under visible light.