The effect of ethanol-polyvinylpyrrolidone dielectric on the characteristics of silver nano-powders synthesized by electro-discharge process

In this study, silver nano-particles (AgNPs) were synthesized by an electro-discharge process between two immersed silver electrodes in four dielectrics: 1) Ethanol, 2) Ethanol-3% PVP, 3) Ethanol-5% PVP, and 4) Ethanol-8% PVP. Further, the effect of input parameters of the process was investigated (current intensity, pulse time duration, and PVP concentration) on the powder rate, structure, phases, morphological characteristics, size distribution, and shape of nanoparticles and then compared by XRD, TEM, UV-Vis, PSA, and SEM tests. The results indicated that the synthesized powder rate rose by increasing the current intensity, pulse time duration, and PVP concentration. By increasing the PVP concentration in ethanol, the pulse time duration and current intensity, the size of the silver nanoparticles shrank. Also, with elevation of PVP concentration in ethanol, the stabilization and dispersion of silver nanoparticles increased and improved, while agglomeration diminished. XRD patterns indicated that the synthesis of silver nanoparticles by electro-discharge process prevents formation of undesirable oxide silver phase. Eventually, the optimum values of input parameters for the synthesis of silver nanoparticles with smallest diameter (25nm-50 nm), best dispersion, stabilization, and the minimum agglomeration were obtained as: Ti = 100 (