Microplasma synthesis of silver nanoparticles in PVP solutions using sacrificial silver anodes

The method of contact glow discharge with the using of “sacrificial” silver anodes have been proposed for synthesis of silver nanoparticles (AgNPs) stabilized by polyvinylpyrrolidone (PVP). Using transmission electron microscopy, it was found that the mean size of AgNPs decrease from 10 to 5 nm with increasing of PVP concentration from 2.5 to 10 g/L. At the same time, the polydispersity index of AgNPs non-monotonically depends on concentration of stabilizer and the narrowest size distribution (less than 15%) was observed at PVP concentration equal to 5 g/L. The electrochemical investigations of Ag anodic dissolution associated with the recorded UV-Vis spectra of the obtained AgNPs solutions suggest that (i) the rate of silver dissolution depend on the nature of regulating agent—NaOH or CH3COONa; (ii) silver anodes are not passivated in the presence of PVP; (iii) unlike to the process of chemical reduction of silver ions by PVP using of the contact glow discharge technique provides a pseudo-stationary process mode, i.e., the stability of rates of nucleation and growth of AgNPs via stability both of Ag+ and solvated electrons concentrations that leads to formation of nearly monodisperse nanoparticles.