Cobalt and Iron Double Doped B-Site Perovskite La0.5Ca0.5CoXFe1−XO3: Synthesis Strategy to Make High-Performance Oxygen Evolution Reaction Catalysts

Abstract

We developed a sustainable solution combustion method to synthesize the perovskite compounds of La_0.5Ca_0.5Co_xFe_1−xO₃ (x = 0, 0.2, 0.4, 0.6, 0.8, 1) to enhance its electrocatalytic activity in oxygen evolution reactions by varying the ratios of iron (Fe) and cobalt (Co) at the B sites. The incorporation of Fe³⁺ and Co³⁺ in varying proportions at the B site is confirmed by PXRD, FTIR, FESEM, HRTEM, and XPS analyses. The synthesized polycrystalline spherical porous material, La_0.5Ca_0.5Co_xFe_1−xO₃, exhibits thermal stability up to 1000 °C. Electrochemical investigations utilizing cyclic voltammetry (CV), linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS), and Tafel plots have identified La_0.5Ca_0.5Co_0.4Fe_0.6O₃ as the most effective electrocatalyst among a series of synthesized perovskites. This material exhibits a Tafel slope of 70.32 mV/dec and an overpotential of 364 mV at a current density of 10 mA/cm². The enhanced OER activity stems from several factors, including a larger electrochemically active surface area, lower charge transfer resistance, a porous structure, and varying proportions of B-site ions.