Green synthesis and characterization of ferrous nanoparticles using Psidium guajava (Linn.) leaf extract

Ferrous nanoparticles were produced using the aqueous leaf extracts of Psidium guajava as a dual reducing and stabilizing agent. A color shift from pale yellow/brown to dark brown/black was observed immediately after reducing ferric chloride (FeCl3) solution (1 mM) to FeNPs by mixing with plant extract (300 mL). The synthesized FeNPs were characterized using UV-Visible spectroscopy and FTIR. Ferrous nanoparticles (FeNPs) were successfully synthesized using aqueous leaf extracts of Psidium guajava as both reducing and stabilizing agents. A rapid color change from pale yellow/brown to dark brown/black indicated the reduction of FeCl₃ (1 mM) upon mixing with 300 mL of plant extract. UV-Visible spectroscopy confirmed nanoparticle formation via a surface plasmon resonance (SPR) peak at 360 nm, indicating Fe³⁺ reduction to Fe²⁺. FTIR analysis revealed key functional groups involved in nanoparticle stabilization and synthesis: C-O stretching (1154–1034 cm⁻¹; alcohols/ethers), alkane C-H (2923 cm⁻¹), alkene C=C (1648 cm⁻¹; flavonoids), and O-H stretching (3417 cm⁻¹; polyphenols/carboxylic acids). These phytochemicals primarily polyphenols, terpenoids, and flavonoids facilitated eco-friendly nanoparticle synthesis, offering a sustainable and nontoxic alternative for environmental and biomedical applications.