EFFECTS OF NONAQUEOUS SOLVENTS ON CATHODIC SULFUR-DIOXIDE REDUCTION

The authors report results obtained when studying the influence of solvents on the solubility of sulfur dioxide, on the excess gas pressure over the solution, and on the discharge capacity during SO//2 reduction at a platinum electrode. The studies have demonstrated the influence of the solvent's donor properties on the characteristics of cathodic SO//2 reduction. The interaction between the solvent and the SO//2 increases with increasing donor number of the solvent, and accordingly decreases the excess gas pressure over the solution within a wide range of temperatures. But, despite the interactions between the solvent with SO//2, the rate of cathodic SO//2 reduction and the discharge capacity of the process increase considerably when electrolytes prepared with high-donor-number solvents are used. Here the solvent also affects surface passivation of the electrode by the solid reduction product.