Electrochemical oxidation of sulfide ions on platinum electrodes

Abstract

This paper treats the electrochemical oxidation of sulfide ions on platinum using cyclic voltametry.  An electrolyte of 3.5% NaCl containing sulfide ions was used as the testing medium.  The effects of scan rate, concentration of sulfide ions and temperature on the cyclic voltamograms were investigated.

Cyclic voltamograms show small currents in the absence of sulfide ions.  In the presence of sulfide ions, the magnitude of the anodic currents in the forward sweep is much more than these in the reverse sweep.  Cyclic voltamograms show three features appear in the forward sweep at potentials of  -0.1, 0.475 and 1.0 V vs Ag/AgCl, respectively.  Peaks currents are increased upon the increase of either the scan rate or temperature.  These peaks are explained to show the possible formed species and the possible electrochemical oxidation reactions at the electrode surface.