Synthesis of Au Nanoparticles by Thermal, Sonochemical and Electrochemical Methods: Optimization and Characterization

The present study concentrates on the synthesis of Au nanoparticles (AuNPs) using aqueous solution of Polyvinylpyrrolidone (PVP) and tetrachloroaurate by different methods as thermal, sonochemical and electrochemical reduction. The PVP has been used as a reducing agent and acts as a stabilizer for Au nano particles that obtained as principal product. In all synthesis procedures, the active radicals resulted from degradation of PVP caused to reduce the Au ions in the solution. A design of experiment (DOE) techniques, the response surface methodology (RSM) and Taguchi method have been used to optimize the selected experimental parameters. As the size of produced nano particles depends on the reaction conditions, we studied the effect of some factors such as the concentration of HAuCl4, the molecular weight of PVP and the time interval for the sonoechemical synthesis of nano particles by the RSM. In electrochemical synthesis, the Taguchi method has been used to optimize the three parameters, interval time of synthesis, applied current density and concentration of HAuCl4. Characterization of AuNPs was carried out by Transition electron microscopy (TEM), UV-Vis spectroscopy, and particle size analyser. The average size of synthesized nanoparticles in optimum condition, estimated by the particle size analyser, were about 130 nm, 26 nm and 91 nm in thermal, sonochemical and electrochemical methods, respectively.