SYNTHESIS OF (LA,SR)COO3 PEROVSKITE FILMS VIA A SOL-GEL ROUTE AND THEIR PHYSICOCHEMICAL AND ELECTROCHEMICAL SURFACE CHARACTERIZATION FOR ANODE APPLICATION IN ALKALINE WATER ELECTROLYSIS

Physicochemical and electrocatalytic properties of perovskite-type La1 -xSrxCoO3 (x = 0, 0.1, 0.2, 0.3, 0.5) synthesized by a low-temperature sol-gel process have been studied. Films were p-type semiconducting w ith a flat-band potential of approximately 0.30 V (Hg/HgO/1 mol dm(-3) KOH). The cyclic voltammogram between 0 and 0.65 V exhibited a pair o f redox peaks (E(0) = 0.43 V) prior to the onset of O-2 evolution at t he oxide film in 1 mol dm(-3) KOH. Among the oxide catalysts prepared, La0.7Sr0.3CoO3 was the most active electrocatalytically. The Tafel sl ope and the reaction order for electrolytic evolution of oxygen were f ound to be 65-72 mV decade(-1) and ca. 1, respectively. Strontium subs titution for La in the mixed-oxide lattice enhanced the electrochemica lly active area; the effect being greatest with 0.3 mol strontium.