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 -C 3 N 4 ) is renowned for its exceptional characteristics in photocatalysis. This work examines the preparation of g -C 3 N 4 from different precursors, and how the presence of silver nanoparticles (Ag NPs) and silver ions (Ag + ) in g -C 3 N 4 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 -C 3 N 4 , the latter provided a much higher yield. Using an easy synthesis approach, Ag NPs were evenly distributed in the g -C 3 N 4 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 -C 3 N 4 and Ag species. Using UV and Vis LED light sources, we investigated both pure g -C 3 N 4 and Ag -g -C 3 N 4 catalysts. For breaking down para-nitrophenol, the silver-modified catalysts performed significantly better than pure g -C 3 N 4 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 -C 3 N 4 -based nanocomposites as effective photocatalysts for environmental remediation. It also explores the benefits of adding silver species to improve performance in degrading pollutants. • Preparation of g -C 3 N 4 proved to be much more efficient from melamine than from urea • For better photocatalytic activity silver ions and nanoparticles were incorporated • Cardamom extract was utilized for environmentally benign bio-inspired silverization • 4-nitrophenol pollutant was efficiently degraded with Ag- g -C 3 N 4 in UV and vis light • No HO • radicals were detected and involved in the degradations with Ag- g -C 3 N 4