Bio-inspired synthesis of Ag-g-C3N4 nanocomposites and their application for photocatalytic degradation of para-nitrophenol

Nanocomposites are promising in advanced materials for environmental applications due to their ability to boost functionality through synergistic effects. Graphitic carbon nitride (g-C₃N₄) is renowned for its exceptional characteristics in photocatalysis. This work examines the preparation of g-C₃N₄ from different precursors, and how the presence of silver nanoparticles (Ag NPs) and silver ions (Ag⁺) in g-C₃N₄ matrices improve their combined effect on photocatalytic activity, specifically in the degradation of para-nitrophenol (PNP), a persistent organic pollutant. From urea and melamine precursors for the preparation of g-C₃N₄, the latter provided a much higher yield. Using an easy synthesis approach, Ag NPs were evenly distributed in the g-C₃N₄ framework, whereas Ag⁺ ions were incorporated by an apparent physical procedure. A bio-inspired, environmentally friendly method was also applied to prepare Ag NPs. The nanocomposites showed improved light absorption and separation of charge carriers due to the synergistic interaction between g-C₃N₄ and Ag species. Using UV and Vis LED light sources, we investigated both pure g-C₃N₄ and Ag-g-C₃N₄ catalysts. For breaking down para-nitrophenol, the silver-modified catalysts performed significantly better than pure g-C₃N₄ in both UV and Vis. The study clarified the functions of Ag NPs and Ag⁺ ions in enhancing photocatalytic activity by examining their involvement in generating reactive oxygen species and degrading pollutants. This work highlights the capability of g-C₃N₄-based nanocomposites as effective photocatalysts for environmental remediation. It also explores the benefits of adding silver species to improve performance in degrading pollutants.