Materials Science Forum, Vol.514-516, 1391-1395, 2006
Electrocatalytic behavior of perovskite-related cobaltites and nickelates in alkaline MediA
Dense ceramic anodes of perovskite-type La1-x-ySrxCo1-zAlzO3-delta (x = 0.45-0.70; y = 0-0.05; z = 0-0.20) and K2NiF4-type La(2)Ni(1-x)MexO(4+delta) (Me = Co, Cu; x = 0-0.20), synthesized by the glycine-nitrate technique, were assessed for oxygen evolution in alkaline media. The lowest overpotentials are observed for (La0.3Sr0.7)(0.97)CoO3-delta, which exhibits a significant oxygen deficiency in combination with high conductivity associated with the A-site cation nonstoichiometry compensation mechanism via Co4+ formation. Perovskite-type cobaltite anodes are essentially stable in alkaline solutions, whilst La2NiO4-based electrodes exhibit degradation at the potentials where the oxygen evolution occurs, probably due to the electrochemical oxygen intercalation in the lattice.
Keywords:perovskite-related oxides;lantanium-strontium cobaltite;nikelate;oxygen evolution;electrocatalytic activity