Plant-Derived Silver Nanoparticles From Senegalia catechu: Antimicrobial Activity and Sunlight-Driven Photocatalysis

Abstract

Silver nanoparticles (Ag NPs) have garnered attention for their environmental and medicinal potential, emphasizing the need for eco-friendly synthesis. This study produces Ag NPs by reacting silver nitrate with aqueous Senegalia catechu leaf extract, a reductant and stabilizer. The formation of Ag NPs was confirmed by a surface plasmon resonance peak at 419 nm in the aqueous colloidal suspension. FTIR spectra showed leaf extract–derived functional groups enabled bioreduction and colloidal stabilization. Their crystallite size was 11.79 nm, according to x-ray diffraction patterns. FESEM/EDS investigation revealed spherical elemental Ag NPs with a geometric mean diameter of 25.8 nm. The synthesized Ag NPs exhibited antimicrobial activity against all tested microorganisms producing inhibition zones of 14 ± 0.3 mm (Escherichia coli), 14 ± 0.2 mm (Staphylococcus aureus) and 13 ± 0.4 mm (Candida albicans). They also showed efficient sunlight-driven photocatalytic degradation of methylene blue, achieving 93.03% removal within 210 min. These results show that Senegalia catechu–mediated Ag NPs could be viable for photocatalytic waste treatment and antimicrobial applications.