One-pot synthesis of highly stable and concentrated silver nanoparticles with enhanced catalytic activity

Well-dispersed silver nanoparticles (AgNPs) were synthesized using a benign, one-pot process based on a low-cost wet chemistry technique. Monoethanolamine was used as a strong reducing agent and poly(acrylic acid) (PAA) was used as a stabilizing agent. After the addition of these reagents to a reaction system, one-pot synthesis of AgNPs was completed in ∼45 min at 75 °C with a reaction efficiency of 92.4%. The average particle size of the aqueous dispersion of AgNPs was 14.83±5.96 nm, and the dispersion remained stable even after 14 months in an ambient dark environment, which may be due to the electrostatic repulsion of the carboxylate anions of the stabilizing agent. The role of PAA in the stabilization of the AgNPs was analyzed via Fourier transform infrared spectroscopy and energy-dispersive X-ray spectroscopy. The highly stable AgNPs in the aqueous system showed high catalytic activity for the reduction of methylene blue and p-nitrophenol in the presence of sodium borohydride as the reducing agent based on pseudo-first-order kinetics.