Impact of Plant Species on the Synthesis and Characterization of Biogenic Silver Nanoparticles: A Comparative Study of Brassica oleracea, Corylus avellana, and Camellia sinensis

Abstract

The choice of plant species is crucial, as different plants provide unique biomolecules that influence nanoparticle characteristics. Biomolecules in plant extracts, such as proteins, amino acids, enzymes, polysaccharides, alkaloids, tannins, phenolics, saponins, terpenoids, and vitamins, act as stabilizing and reducing agents. This study explores the synthesis of silver nanoparticles (AgNPs) using leaf extracts from collard greens (Brassica oleracea var. acephala), hazelnut (Corylus avellana var. avellana), and green tea (Camellia sinensis). NPs were synthesized using silver nitrate (AgNO3) solution at two different molarities (1 mM and 5 mM) and characterized by UV–Vis spectroscopy, XRD, TEM, and FTIR. The Surface Plasmon Resonance (SPR) peaks appeared rapidly for hazelnut and green tea extracts, within 30 and 15 min, respectively, while collard greens extract failed to produce a distinct SPR peak. X-Ray Diffraction confirmed the formation of face-centered cubic silver. TEM analysis revealed high polydispersity and agglomeration in all samples, with particle size generally decreasing at higher AgNO3 concentrations. However, hazelnut extract showed a slight increase in size at higher molarity. Among all samples, green tea-derived AgNPs synthesized with 5 mM AgNO3 were the smallest and least polydisperse, highlighting the significant role of plant type in optimizing nanoparticle synthesis.