Cobalt and Iron Double Doped B‐Site Perovskite La _0.5 Ca _0.5 Co _X Fe _1−X O ₃ : 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 0.5 Ca 0. 5Co x Fe 1−x O 3 ( 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 Fe 3+ and Co 3+ in varying proportions at the B site is confirmed by PXRD, FTIR, FESEM, HRTEM, and XPS analyses. The synthesized polycrystalline spherical porous material, La 0.5 Ca 0. 5Co x Fe 1−x O 3 , 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 0.5 Ca 0.5 Co 0.4 Fe 0.6 O 3 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/cm 2 . 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.