EFFECT OF ADDITION OF ALKALINE-EARTH CARB ONATES ON THE OXYGEN REDUCTION REACTION IN MOLTEN ALKALI CARBONATES

The exchange current densities (i0) of oxygen reduction on a gold elec trode have been measured by a potential step method in order to study the effect of the addition of alkaline earth carbonates in molten alka li (Li/K=62/38 mol%) carbonates. And simultaneously, steady state pola rizations have been measured. While BaCO3, SrCO3 and CaCO3 were adopte d as alkaline earth carbonates, it was identified that i0 and the stea dy state current were increased by every alkaline earth carbonate addi tion. In the case of BaCO3 addition, the most remarkable effect was ob served. Typical results are i0=11.7 mA/cm2 from BaCO3 addition, i0=8.6 mA/cm2 from no addition under Po2/Pco2 = 0.9/0.1 atmosphere at 923K.