Electrochemical Reactions in a Pure Na2 SO 4 Melt

Abstract

Cyclic voltammetry and chronopotentiometry were used to study the electrochemical reduction reactions of SO3 gas, O2− and SO42− ions in a Na2SO4 melt at 900°C. The reduction reaction of SO3 follows a ce mechanism: SO3 first reacts chemically with SO42− to form S2O72− and then proceeds via a one-electron electrochemical reduction reaction to form S03−. The reduction of peroxide O2− ions forms either O2− or both O2− and superoxide O22− ions. Sulfate ions are subjected to decomposition at either very positive or very negative potentials. At very high positive potentials, sulfate ions decompose to evolve SO2 and O2 gases, in addition superoxide ions are also formed. At very negative potentials, sulfate ions decompose to form sulfide and peroxide. © 1983, The Electrochemical Society, Inc. All rights reserved.