Mediated electrosynthesis of silver nanoparticles in a two-phase water—isooctane system

Abstract

Efficient electrosynthesis of silver nanoparticles (AgNPs) in bulk solution of a two-phase water—isooctane system is carried out by electrolysis in an undivided cell in the presence of methylviologen (MV2+) used as a mediator. Silver nanoparticles are formed in the aqueous phase of the system as a result of the electroreduction of Ag+ ions generated in situ by dissolving the Ag anode at potentials of the redox couple MV2+/MV·+. The obtained AgNPs are stabilized by an anionic surfactant, sodium dioctyl sulfosuccinate, and are distributed throughout both the aqueous and the organic phases. All the nanoparticles would transfer to the organic phase after the obtained solution was kept in the dark for 48 h. In addition to dissolution, the Ag anode undergoes dispersion during electrolysis, therefore the total current yield of the obtained AgNPs is 175%. According to electron microscopy, the formed AgNPs are polydisperse and their size ranges from 5 to 71 nm. A surface plasmon resonance of AgNPs in the solution obtained after electrolysis was observed in the region of 418–463 nm.