Effect of Copper Substitution on the Electrocatalytic Activity of ZnMn₂O₄ Spinel Embedded on Reduced Graphene Oxide Nanosheet for the Oxygen Evolution Process

The fabrication of a proficient and durable electrocatalyst for the OER process is the most crucial parameter in the water splitting process. A simple and basic procedure was used in this study to create Cu-substituted ZnMn₂O₄/rGO spinel nanosized composite as an electrode for OER. The morphological and structural investigations indicate that the carbon based spinel successfully bonds, and the addition of copper into rGO results in a substantial change in its electrocatalytic process for the oxygen evolution process. Zn_1−xCu_xMn₂O₄/rGO with x = 0.6 has a minimal overpotential of 150 mV at a current density of 10 mAcm⁻², low onset potential of 1.40 V and a smaller Tafel slope of 31 mV dec⁻¹ than other substitution. The electrocatalyst also exhibits high ECSA (632.5 cm²), R_f (1580), and exceptional stability, all of which improve OER performance. These analysis confirm the enhanced electrocatalytic efficiency of the hybrid material to catalyze OER for energy generation, and other fields.