Environmentally Benign and Large-Scale Synthesis of Monodisperse Oleate-Protected Silver Nanoparticles in Ethanol

Abstract

An environmentally benign solvothermal process was introduced to synthesize monodisperse silver nanoparticles (Ag NPs). Silver nitrate (AgNO3) was reduced by ethanol which was also used for recyclable solvent. The as-synthesized Ag NPs were stabilized by oleate. Effects of reaction temperature, reaction time, AgNO3 concentration as well as molar ratio of sodium oleate and AgNO3 on the formation and surface plasmon resonance (SPR) were determined by means of UV–Vis spectrophotometer. TEM and XRD were used to characterize the size, morphology and crystalline structure of Ag NPs. The excessive AgNO3 over sodium oleate and high concentration of AgNO3 are favorable for the synthesis of monodisperse Ag NPs in large scale. The characteristic SPR absorption of Ag NPs centers at ca. 430 nm despite of reaction temperature, reaction time and even AgNO3 concentration. The nucleation and growth of Ag NPs completed in a very short period of time, showing the high efficiency of our synthetic route for the synthesis of uniform Ag NPs.