Green synthesis of biofunctionalized iron oxide nanoparticles using lagerstroemia indica: structural characterization, antioxidant potential, and corrosion inhibition efficiency

Abstract

This study reports a green, one-pot synthesis of biofunctionalized iron-oxide nanoparticles (Fe3O4/γ-Fe2O3) using Lagerstroemia indica leaf extract as a combined reducing/capping system. X-ray diffraction confirms mixed magnetite/maghemite phases, while UV–Vis and FTIR support phytochemical surface passivation. SEM-EDX shows agglomerated nanoscale domains enriched in Fe and O; DLS and ζ-potential indicate colloidal stabilization by plant-derived polyphenols. Antioxidant activity quantified by DPPH, ABTS, and total antioxidant capacity increases with dose, achieving up to 92.9% DPPH scavenging at 200 μg ml−1. Potentiodynamic polarization and electrochemical impedance spectroscopy in 0.5 M HCl demonstrate mixed-type inhibition with maximum efficiency of ∼75% at 200 mg l−1, attributed to synergistic adsorption of phytochemical shells and mixed-valence Fe centers that impede charge transfer. The aqueous, additive-lean process furnishes multifunctional nanomaterials with practical antioxidant and corrosion-protection performance.