Anodic Oxidations of Sulfite, Thiosulfate, and Dithionite at Doped PbO2 ‐ Film Electrodes

Abstract

The anodic oxidations of , , and were examined at pure and doped electrodes at 25 and 65°C in a buffer (pH 10). Values of half‐wave potentials vary only slightly with the identity of dopant. The numbers of electrons transferred in the electrochemical processes (n, eq mol−1), as determined by coulometry and hydrodynamic amperometry, are consistently less than expected for complete oxidation to sulfate . Estimated values of heterogeneous rate constants and reaction orders are also compared. Results of wet‐chemical analyses are interpreted to indicate that some dithionate is formed during the anodic reactions. A possible mechanistic scheme based on anodic transfer of oxygen is considered.