Electrochemical Reduction of Elemental Sulfur in Ethylene Glycol Electrolyte

Abstract

The work is devoted to the study of the mechanism of reduction of elemental sulfur from ethylene glycol. For this purpose, linear and cyclic voltampere polarization curves were recorded. The influence of sulfur concentration in ethylene glycol electrolyte, potential unfolding rate and temperature on the sulfur reduction process was investigated. By recording the cyclic polarization curve, the range of potentials at which the reduction of elemental sulfur and its anodic oxidation occur was determined. It has been established that an increase in the concentration of sulfur in the electrolyte and temperature raises the speed of its reduction, and the process itself is controlled by the diffusion of sulfur ions to the cathode surface. In addition, the polarization curves on the platinum rotating disc electrode were recorded. The obtained data, namely the rectilinear dependence of ip on the rotation speed of the electrode (ω) to the power of 0.5, confirm the proposal that the process of reduction of elemental sulfur is accompanied by diffusion polarization. The dependence of the current density on the rotation speed of the electrode to the power of 0.5 at different potentials showed that the process of reduction of elemental sulfur in non-aqueous ethylene glycol at potentials of (0.25÷0.4 V) is accompanied by diffusion polarization, whereas at potentials above 0.4 V, it is accompanied by electrochemical polarization. Keywords : Sulfur ions, electroreduction, polarization, scanrate.