Hydrothermal synthesis of Ag₂O-modified Zn₂SnO₄ for improved visible-light photocatalytic performance on ciprofloxacin degradation

Visible-light-driven photocatalysis offers a promising and effective approach for mitigating antibiotic contamination. Therefore, this study aims to modify Zn₂SnO₄ with Ag₂O using a hydrothermal route to enhance its visible-light photocatalytic activity for ciprofloxacin degradation. The resulting Ag₂O-Zn₂SnO₄ heterostructures were characterized using XRD, FE-SEM coupled with EDS, TEM, and UV-Vis DRS. XRD analysis confirmed that the Ag₂O-Zn₂SnO₄ composites exhibited high crystallinity and purity, as validated through Le Bail refinement. Incorporating Ag₂O at varying loadings (5, 7.5, and 10%) induced notable morphological transformations in Zn₂SnO₄, shifting from an octahedral structure to flower-like and irregular spherical forms. TEM imagery further revealed that spherical Ag₂O particles were uniformly distributed on the Zn₂SnO₄ surface. In addition, the band gap of the composites decreased from 3.84 to 2.92 eV, indicating enhanced visible-light responsiveness. Pure Zn₂SnO₄ showed negligible photocatalytic activity toward ciprofloxacin, achieving only 0.27% degradation. The composites also demonstrated substantial photocatalytic performance at all Ag₂O loadings, with degradation efficiencies of 8.60%, 40.77%, and 38.22%, respectively. These findings highlight the crucial role of Ag₂O in improving photocatalytic activity, attributed to increased visible-light absorption and the formation of p-n heterojunctions that promote efficient charge separation and suppress electron-hole recombination. • Ag₂O-modified Zn₂SnO₄ photocatalyst was first synthesized via a simple hydrothermal method. • Ag₂O addition induced notable morphological changes and enhanced visible-light absorption of Zn₂SnO₄. • The Ag₂O-Zn₂SnO₄ composites showed markedly improved photocatalytic degradation of ciprofloxacin under visible light.