Partially substituted La for Sm in Sm 0.8 Sr 0.2 NiO 3 : An efficient electrocatalyst towards alkaline water splitting

Abstract

Perovskite-type oxides having composition LaxSm0.8-xSr0.2NiO3 (0 ≤ x ≤ 0.6) were explored for their ability to act as facilitators for oxygen evolution reaction in alkaline media. Synthesis of the materials was conducted through sol-gel procedure via malic acid. The materials underwent advanced physicochemical characterization utilizing cutting-edge techniques, namely Scanning Electron Microscope (SEM) and X-Ray Diffraction (XRD). These analyses provided crucial details about the material’s surface morphology and crystalline structure, opening up exciting possibilities for their diverse applications. Cyclic voltammetry and Tafel Plot were observed for the electrochemical analysis in 1M KOH (25℃). An investigation on the anodic polarization of oxides revealed an increased electrocatalytic activity when La was partially substituted for Sm in Sm0.8Sr0.2NiO3. La0.6Sm0.2Sr0.2NiO3 was found to be most active at 800 mV with current density, j = 184.1 mA/cm2. Tafel experiment was conducted in 1M KOH at varying temperatures to determine thermodynamic properties like standard electrochemical energy of activation (ΔH˚#el), standard enthalpy of activation (ΔH˚#) and standard entropy of activation (ΔS˚#).