Graphene oxide-driven charge modulation in AgVO3/BiOI multi-heterojunctions for superior photocatalytic removal of antibiotics under visible light

Abstract

The widespread contamination of water resources by persistent pharmaceutical residues, such as tetracycline, presents a critical environmental challenge that requires sustainable remediation technologies. Herein, we report the rational design and hydrothermal synthesis of a novel ternary graphene oxide/silver vanadate/bismuth oxyiodide (GO/AgVO3/BiOI) nanocomposite engineered for visible-light-driven photocatalytic degradation of tetracycline. Comprehensive structural and spectroscopic analyses (XRD, FTIR, XPS, SEM–EDS, BET, UV-DRS, and PL) confirmed the successful formation of an interfacial heterojunction between GO, AgVO3, and BiOI. The optimized composite exhibited a high surface area (52.43 m2/g) and a narrowed bandgap (1.66 eV), promoting efficient light absorption and charge carrier separation. Under visible-light irradiation, the GO/AgVO3/BiOI catalyst achieved a remarkable 95.6% tetracycline degradation within 60 min, outperforming binary and pristine counterparts by over sevenfold. Radical trapping experiments revealed that •OH and h⁺ were the dominant reactive species, while GO acted as an efficient electron mediator, facilitating interfacial charge transport and suppressing recombination. The nanocomposite also demonstrated excellent photostability and recyclability across multiple cycles. This work introduces a cost-effective and robust multi-heterojunction photocatalyst with superior visible-light activity, offering a promising route toward sustainable environmental purification and next-generation wastewater treatment technologies.