Electrocatalytic Activity of Sr-Doped Lanthanum Cobaltate for Oxygen Evolution Reaction in Alkaline Medium

La1 – xSrxCoO3 (x = 0.1, 0.2, 0.3, 0.4, and 0.5) were prepared by the alginic acid sol–gel route and characterized by thermo gravimetric analysis (TGA), Fourier transform infrared (FT-IR), X-ray diffraction (XRD), and scanning electron microscope (SEM) techniques. The electrocatalytic activity of fabricated oxide electrodes (Ni/oxide) was studied for oxygen evolution reaction (OER) in an alkaline medium. The cyclic voltammetry of oxide electrodes shows a pair of redox couple at anodic peak potential (Epa) = 400 ± 6 mV and cathodic peak potential (Epc) = 296 ± 8 mV. The observed values of electrode kinetic parameters such as the Tafel slope (b) lie between 91 and 126 mV dec–1 and current density (j) lie between 17.0–73.1 mA cm–2 at 0.85 V. The Sr-substitution in lanthanum cobaltate matrix improve electrocatalytic activity for OER in an alkaline medium and maximum improvement was observed in the case of 0.4 mol Sr-substituted oxide. The order of reaction (p) with respect to the concentration of [OH–] is found unity and the highly negative value of entropy of the reaction indicated the oxygen evolution follows the same mechanism and involves the adsorption of the reaction intermediate.