Electrochemical activity of solid solutions La1 -x Sr x CoO3 in the oxygen electroreduction reaction in carbonate melts
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Solid solutions Lad1-xSrxCoO3 are synthesized. An X-ray diffraction study reveals the formation of a rhombohedrically distorted perovskite-like phase. The kinetics and mechanism of the electroreduction of oxygen at the synthesized compounds in Li2CO3-K2CO3 (62: 38 mol %) and Na2CO3-Cs2CO3 (39:61 mol %) melts are studied by static coulometry and chronoamperometry. The exchange current grows with the strontium content in samples. The obtained apparent reaction orders of 0 and 0.14 by O2 and CO2 contradict all mechanisms offered earlier for the oxygen electroreduction at a gold electrode. A new mechanism is offered, in which the limiting step is the transfer of oxygen ions from the solid phase into the melt with corresponding changes in the electron subsystem of the electrode material.
KeywordsOxygen Reduction Gold Electrode Electrochemical Activity Oxide Electrode Geometrical Surface Area
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