Nanocellulose-Supported Dual S-Scheme SnWO₄/Cu₂O/Ag₂WO₄ Heterojunction for Enhanced Photodegradation of Amoxicillin

A dual S-scheme nanocellulose-based SnWO₄/Cu₂O/Ag₂WO₄ (NC-SCA) heterojunction photocatalyst was synthesized via ultrasonication followed by a hydrothermal method for the efficient photodegradation of amoxicillin (AMX). Under UV-vis light irradiation, the NC-SCA photocatalyst exhibited an impressive 97.40% AMX degradation within 30 min, attributed to its improved optical absorption and superior charge migration. The characterization techniques, including XRD, FTIR, PL, and UV-vis spectroscopy, confirmed the successful integration of nanocellulose with SnWO₄/Cu₂O/Ag₂WO₄. XPS and ESR analyses provided insights into the S-scheme charge migration mechanism within the heterojunction. Further, the trapping experiments identified hydroxyl (^•OH) and superoxide radicals as the primary reactive species. The photocatalyst displayed a specific surface area of 115.9 m²/g, offering a large active surface for photodegradation. Operational parameters such as the photocatalyst dosage, pH, and AMX concentration were systematically optimized. The NC-SCA photocatalyst exhibited high stability, retaining around 85% efficiency after seven cycles. This study presents an innovative strategy for designing high-performance photocatalysts addressing the limitations of conventional materials.