Photocatalytic norfloxacin degradation enabled by a dual S-scheme nanocellulose-based Ag2WO4/NiO/MoO3 tertiary heterojunction

Abstract

The escalating presence of antibiotic contaminants, such as norfloxacin (NFX), in water resources poses a pressing environmental challenge, demanding the development of innovative and sustainable remediation technologies. Herein, we report the design and fabrication of a novel S-scheme heterojunction photocatalyst, comprising Ag₂WO₄, NiO, and MoO₃ nanoparticles anchored onto a nanocellulose matrix (NC–ANM), for the efficient photocatalytic degradation of NFX under visible light irradiation. Comprehensive structural, morphological, and physicochemical characterization techniques, including XRD, XPS, FTIR, FESEM, and HRTEM, corroborated the successful formation of the heterojunction and its constituent phases. Optical and electrochemical analyses, utilizing UV-vis DRS, PL, and EIS, revealed enhanced visible light absorption, efficient charge separation, and prolonged charge carrier lifetimes, key attributes underpinning the superior photocatalytic activity of the NC–ANM heterojunction. Mechanistic investigations, employing LC-MS and ESR spectroscopy, confirmed the S-scheme charge transfer pathway, leading to the generation of reactive oxygen species (˙OH and ˙O₂⁻) that efficiently degrade NFX. The heterojunction demonstrated remarkable photocatalytic performance, achieving 99.6% NFX degradation within 30 minutes under optimized conditions. This study not only showcases the potential of NC–ANM as a highly efficient and sustainable photocatalyst for wastewater treatment but also provides valuable insights into the design and engineering of advanced S-scheme heterojunctions for environmental remediation applications.