Electrochemical Reduction of Oxygen and Nitric Oxide at Low Temperature on La1−x Sr x FeO3−δ Cathodes

Abstract

A series of six strontium-substituted lanthanum ferrites (La1−x Sr x FeO3−δ, x = 0.00, 0.05, 0.15, 0.25, 0.35, and 0.50) were synthesized using the glycine-nitrate process and evaluated as cathodes for the electrochemical reduction of oxygen and nitric oxide in the temperature range 200 to 400 °C, using cone-shaped electrodes and cyclic voltammetry. It was shown that the ferrites had a higher activity towards the electrochemical reduction of nitric oxide than towards the electrochemical reduction of oxygen, in the investigated temperature range. The highest activity towards the electrochemical reduction of nitric oxide was found for La0.95Sr0.05FeO3−δ at 400 °C. This compound also showed the highest activity towards the electrochemical reduction of oxygen at 400 °C. The highest apparent selectivity was found for the compound LaFeO3 at 200 °C. The materials showed ability to oxidize nitric oxide to nitrogen dioxide.