Electrochemical Processes of Sulfide in NaCl Electrolyte Solutions on Mercury Electrode

The electrochemical processes of sulfide in NaCl electrolyte solutions were studied using stripping cyclic voltammetry, differential capacity and chronoamperometric measurements. Some new effects were observed and are here discussed. At potentials around −0.1 to −0.3 V a pair of Faradaic adsorptive peaks, which can only be observed in the presence of chloride, is attributed to the formation of HgCl $\rm{ {_{4}^{2-}}}$ ion from the deposited layer of HgS. A second pair of peaks of purely capacitive character was observed at −0.4 V. This is the result of the reorientation and partial desorption or transformation of HgS layers. The formation and dissolution of HgS layers on mercury has been well investigated previously. We observed some new effects after depositing approximately ten layers of HgS and attributed this to the formation of polysulfides at positive potentials.