Green Synthesized Ag Nanoparticles for Bio-Sensing and Photocatalytic Applications

In this work, sensing and photocatalytic activities of green synthesized silver nanoparticles (Ag NPs) are investigated. Ag NPs have been synthesized by the reduction of silver nitrate (AgNO₃) using different leaf extracts. An optimum surface plasmon resonance (SPR) behavior is obtained for neem leaf extracts because of the presence of a high concentration of diterpenoids, as evidenced from gas chromatography mass spectroscopy results. The underlying mechanism for the formation of Ag NPs is highlighted. The Ag NPs are in spherical shape and exhibit the hexagonal crystal phase and also show a good stability. The biosensing property of the Ag NPs is evaluated using mancozeb (MCZ) agro-fungicide, and the SPR peak position exhibited a linear response with MCZ concentration. The sensitivity is found to be 39.1 nm/mM. Further, the photocatalytic activity of Ag NPs is tested using 0.5 mM MCZ solution as a model under UV-visible illumination. It is observed that photocatalytic activity is caused by the formation of reactive oxygen species. Therefore, the green synthesized Ag NPs are potential candidates for biosensing and photocatalytic applications.