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

La 1 – x Sr x CoO 3 ( 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 ( E pa ) = 400 ± 6 mV and cathodic peak potential ( E pc ) = 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.