Highly Active FeCo Bimetallic Oxyhydroxide for Efficient Oxygen Evolution in Water Electrolysis

The development of highly efficient oxygen evolution reaction (OER) electrocatalysts is crucial for advancing clean energy technologies. This study employed electrodeposition to fabricate a highly efficient and stable Fe-doped CoOOH electrocatalyst. During the OER process, the catalyst undergoes substantial electrochemical reconstruction, resulting in its in-situ transformation into a FeCo bimetallic oxyhydroxide (Fe-CoOOH) enriched with active sites. The introduction of Fe significantly enhances the intrinsic conductivity of the reconstructed material, thereby facilitating improved charge transfer kinetics. Furthermore, leveraging bimetallic synergy, the optimized catalyst exhibits a notably reduced Tafel slope of 30 mV dec⁻¹. This kinetic enhancement indicates a shift in the rate-determining step (RDS) from the conventional *OOH formation step (approximately 120 mV dec⁻¹), typical of cobalt-based oxyhydroxides, toward a mechanism dominated by electron transfer. The reconstituted Fe-CoOOH demonstrates exceptional electrocatalytic performance, requiring an overpotential of merely 283 mV to deliver a current density of 50 mA cm⁻².In summary, this work successfully prepared a high-performance bimetallic oxyhydroxide OER catalyst through an electrochemical reconstruction strategy. Fe doping played a critical role in enhancing electrical conductivity and, more importantly, in modulating the electronic structure of the reconstruction product, which led to a reduced Tafel slope and a fundamental change in the RDS. These findings provide valuable insights for the rational design of efficient bimetallic electrocatalysts for energy conversion applications.