Engineered Ag/ZnO/g-C₃N₄ ternary nanocomposites: optimizing silver loading for superior sunlight-driven dye photodegradation

Water pollution remains a pressing global environmental concern, with the textile industry recognized as a major contributor to both water consumption and contamination, particularly through the release of synthetic dyes. Therefore, the development of efficient treatment technologies targeting dye pollutants in textile wastewater is imperative. In this study, a ternary Ag/ZnO/g-C₃N₄ nanocomposite was successfully synthesized via an ultrasonication-assisted method with Ag content variation (2 mol% − 8 mol%). Comprehensive structural and morphological characterizations were carried out using FT-IR, XRD, SEM, SEM-BSE, TEM, PL, and XPS. FT-IR and XRD analyses confirmed the presence of characteristic functional groups and the crystalline phases of ZnO and associated components. SEM-BSE imaging revealed uniform distribution of Ag particles with the composite matrix, corroborated by the XPS analysis, which identified the metallic state of Ag. Comprehensive particle properties measurement indicates produced nanocomposite has shown photocatalytic activity in degrading methylene blue (MB) solution. The incorporation of Ag above 2% accelerates photocatalytic activity and could reduce MB pollutant by around 96% in 30 min sunlight irradiation. Incorporating Ag influences the number of active sites, resulting in a highest surface area of 27.49 m²/g at 6% Ag concentration. The possible particle formation mechanism and enhanced photocatalytic reaction were discussed in this study.