Fabrication of Highly Stable Silver, Platinum and Gold Nanoparticles via Microemulsions： Influence of Operational Parameters

Abstract: The Ag, Pt and Au nanoparticles were synthesized by mixing of two microemulsions containing a proper metal salt or reducing agent in aqueous phase. The microemulsi ons used in this study were composed of n -heptane/ water/sodium bis (2-ethylhexyl) sulphosuccinate (AOT)/metal salt or reducing agent. The effect of different parameters such as metal precursor concentration in aqueous phase [M + ], water to AOT molar ratio ( W ) and reducing agent concentration in aqueous phase on the reaction were investigated. The reaction progress was monitored by time resolved UV-Vis absorption spectroscopy. Transmission electron microscopy (TEM) micrographs revealed that the nanoparticles obtained were spherical. It was found that with increasing the met al salt concentration, and also W value larger particles were formed. The resultant nanometal colloids were highly stable and no precipitated particles have been observed during three months time periods. Key words: Nano materials, non-ferros metals and alloys, transmission electron microscopy.