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
Abstract
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 with 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 of redox peaks (E0= 0.43 V) prior to the onset of O2 evolution at the oxide film in 1 mol dm–3 KOH. Among the oxide catalysts prepared, La0.7Sr0.3CoO3 was the most active electrocatalytically. The Tafel slope and the reaction order for electrolytic evolution of oxygen were found to be 65–72 mV decade–1 and ca. 1, respectively. Strontium substitution for La in the mixed-oxide lattice enhanced the electrochemically active area; the effect being greatest with 0.3 mol strontium.