Electrochemical Behavior of Sulfur in Aqueous Alkaline Solutions

The kinetics and mechanism of the electrode oxidation-reduction of sulfur on an electrically conductive sulfur–graphite electrode in an alkaline solution was studied by the potentiodynamic method. To examine the mechanism of electrode processes occurring during AC polarization on a sulfur–graphite electrode, the cyclic polarization in both directions and anodic polarization curves were recorded. The kinetic parameters: charge transfer coefficients (α), diffusion coefficients ( D ), heterogeneous rate constants of electrode process ( k s ), and effective activation energies of the process ( Е а ) were calculated from the results of polarization measurements. An analysis of the results and calculated kinetic parameters of electrode processes showed that discharge ionization of sulfur in alkaline solutions occurs as a sequence of two stages and is a quasireversible process.