Oxygen and chlorine electrodes on semiconductive SnO2 in molten LiCl-KCl eutectic

The oxidation of oxide (O2−) and chloride ions were studied at tin oxide electrodes in molten LiCl-KCl eutectic at 450° C using voltammetric techniques. The polarization characteristics of the oxide semiconductor electrode were compared with that of Pt in the case of the oxygen electrode and with that of glassy carbon in the case of chlorine evolution. Both electrode reactions on tin oxide were found to be somewhat less reversible compared with the results of Pt and GC. It is suggested that the observed irreversibility is related to the electron tunnelling process through the space charge barrier formed at the semiconductor surface.