Optimization of silver nanoparticles synthesis: effects of trisodium citrate parameters and reaction temperature

Abstract

Silver nanoparticles (AgNPs) exhibit unique optical and chemical properties that enable broad applications in sensing, catalysis, and nanomedicine. This study optimized AgNPs synthesis using the Turkevich method, in which silver nitrate (AgNO₃) serves as the silver precursor and trisodium citrate (TSC) acts as both the reducing and stabilizing agent. The effects of a fixed AgNO₃ concentration of 0.034 g (0.06 mM), TSC addition timing, storage conditions, reaction temperatures of 70°C, 80°C, and 90°C, and TSC concentrations of 0.5 g (0.136 mM), 1.0 g (0.272 mM), and 1.5 g (0.408 mM) were investigated. Characterization using FESEM and EDX, UV-VIS spectroscopy, Zeta Potential, and Zeta Sizer (dynamic light scattering, DLS) revealed that higher temperatures (≥80°C) combined with higher TSC concentrations of 1.0 g and 1.5 g produced smaller, more stable nanoparticles of 72.85–90.38 nm with a polydispersity index (PdI) of 0.5–0.7, indicating good uniformity. UV-VIS spectra confirmed AgNPs formation, with surface plasmon resonance peaks at 436–519 nm. Zeta potential values below –40 mV at higher TSC concentrations indicated excellent colloidal stability, whereas lower temperatures and insufficient TSC led to aggregation. Storage at room temperature accelerated oxidation and particle growth. Optimal synthesis conditions of 80°C to 90°C with 1.0 g to 1.5 g of TSC offer a reproducible method for fabricating stable AgNPs.