Novel Ag₂O_x-Infused Silica-Titania composites for enhanced photocatalytic degradation of Bisphenol A and 4-Nitrophenol under visible light

In this study, we introduce Ag₂O_x-infused silica-titania (ST) composites with varying concentrations (Ag: 0.5, 1, 1.5, 2 wt%) synthesized through a simple sol–gel and wet impregnation method. These composites demonstrate exceptional photocatalytic efficiency for the degradation of organic pollutants, specifically Bisphenol A (BPA) and Nitrophenol-4 (4-NP). Detailed characterization, including XRD, UV-DRS, FESEM, TEM-Elemental mapping, BET, PL and XPS analyses confirmed the unique structural features and composition of the materials. Among the composites, the Ag₂O_x(1 wt%)/ST composite microspheres exhibit the highest catalytic activity, with a total pore volume of 0.734 cm³/g, a surface area of 285.18 m²/g, and a significantly reduced bandgap of 2.4 eV. Under visible light irradiation, Ag₂O_x(1 wt%)/ST composites achieve remarkable photocatalytic degradation, removing 98 % of BPA and 4-NP of 97 % within 180 min. These composites outperform bare TiO₂ by 7.6 times in terms of surface area, providing a superior platform for efficient charge separation and enhanced photocatalytic performance. The formation of a p-n junction at the interface of Ag₂O_x(1 wt%)/ST composites contributes to the effective charge separation, boosting photodegradation efficiency. Kinetic studies reveal strong correlation coefficients (R² = 0.972 min^-1 and 0.981 min^-1) for BPA and 4-NP degradation, respectively. The Ag₂O_x(1 wt%)/ST composites represent a significant advancement in eco-friendly water purification, offering a promising solution for efficient and sustainable water treatment.