The medium effect on electrodissolution of adsorbed or suspended Ag nanoparticles

Abstract

Electrochemical behaviour of six types of Ag nanoparticles (three stabilised by citrate and three others stabilised by polymers) was studied on carbon screen-printed electrode and glassy carbon rotating disc electrode. A stationary electrode was used as a support for adsorbed nanoparticles, whereas the rotating disc electrode was applied for experiments in nanoparticles suspension. Peak shaped cyclic voltammograms obtained for immobilised nanoparticles indicate their electro-dissolution and electrodeposition of silver in the backward scan. The given peak shape and its position on potential scale depend both on the type of nanoparticles and the supporting electrolyte. When aggregation of Ag nanoparticles was detected by UV–vis spectroscopy, splitting of an anodic peak corresponding to electrodissolution of silver in neutral phosphate buffer or NaOH solution is seen. Injection of a fraction of microgram of Ag nanoparticles was detected in chronoamperometric experiments on rotating disc electrode. However, in the presence of H2O2, the effect of nanograms of silver was seen on voltammetric curve indicating electrocatalytic amplification.