Characteristics and electrochemical mechanisms of a nanosilver solution formed by anodic dissolution with high DC voltage

Abstract

Nanosilver solution, prepared by anodic dissolution with high DC voltage in doubly distilled water, is free of undesirable chemicals and forms a highly pure product which is suitable for different applications, especially in the medical and pharmaceutical fields. In this study high DC voltage electrolysis was implemented to form nanosilver solutions with varying electrode diameters, anode-cathode distances, and electrolysis duration. The process was monitored while the cell was in operation, and the characteristics of the resulting solution were analysed afterwards. Cell reactions included: colour changes in the solution bulk due to the reduction of silver ions forming nanoparticles, anodic dissolution of silver, intense gas evolution at both electrodes, and chemical reactions in the solution causing nanosilver formation. UV-Vis characteristics, particle size distribution, transmission electron microscopy (TEM) images, solution concentrations, conductivities, and ζ-potentials were all found to depend on the electrode’s distances, temperature, electrolysis duration, and current density. Nanosilver preparation can thus be considered a combination of electrochemical reactions (such as silver dissolution at anode and water decomposition to generate hydrogen and oxygen), and chemical reactions between the electrolytic products from the solution bulk.