Optical and electrochemical study of the sulphide/silver system

Abstract

The behaviour of sulphide species at a silver/electrolyte interface along with the electrodeposition of thin Ag₂S films have been studied by a combination of electrochemical and <i>in situ</i> optical methods. The potential region between −1.08 and −0.470 V (nhe), pre-peak zone, is mainly characterized by a reversible process at −0.870 V, overlapping and catalysing the <i>her</i>, ascribed to the formation of an Ag−(Sh−_ads bond. Phase Ag₂S deposits were found to fit a linear relationship between reflectance, in the blue region, and charge. The oxidation of surface Ag₂S (postwave) is readily observed by differential reflectance at potentials positive of the onset of bulk Ag₂S formation. The rough silver surface brought about by the reduction of Ag₂S allows a strong coupling between photons and surface plasmons.