Meniscus behavior of metals and oxides in molten carbonate under oxidant and reducing atmospheres .2. Electrode reactions

Hydrogen oxidation and oxygen reduction in molten carbonate were investigated, using direct optical observation of the meniscus at the electrode, in conjunction with electrochemical measurements. Meniscus heights and currents at various electrode materials were measured in oxidant and reducing atmospherics at 600 degrees C and 650 degrees C. Temperature has a strong effect on oxygen reduction but not on hydrogen oxidation. The meniscus region makes a major contribution to oxygen reduction. On the other hand, hydrogen oxidation takes place mainly at the submerged part of the electrode contacting the molten carbonate. This difference can be explained by the difference in solubility between hydrogen and oxygen.