Mediation of Oxidation and Spin States of Fe/P‐CoO₂ Core–Shell Structures Catalysts for Oxygen Evolution Reaction

Abstract Low‐cost, high‐performance oxygen evolution reaction (OER) catalysts are crucial for water electrolysis. Herein, the synthesis of low‐cost Fe/P‐CoO₂ amorphous catalyst is reported, achieving an ultralow overpotential of 260 mV at 10 mA cm⁻² in 1 m KOH. Assembled Pt/C||Co_0.75Fe_0.25P/MWCNTs system affords a current density of 10 mA cm⁻² at a cell voltage of only 1.53 V, which is much better than that of the benchmark Pt/C||RuO₂ system (1.62 V). Such performance lies ointhe electronic mediation of active sites with asymmetric Co‐ and Fe‐coordination structures with different d‐band occupancy. The combination of Fe‐cationic and P‐anionic coordination effectively optimizes the adsorption of OER intermediates (OH^*, O^*), promoting direct O^*─O^* coupling and avoiding the formation of unstable OOH^* intermediate. Benefiting from these advantages, Co_0.75Fe_0.25P/MWCNTs demonstrate excellent OER activity and stability, surpassing the benchmark RuO₂. The proposed strategy presents a novel approach for the synthesis of cost‐effective, highly efficient, and durable electrocatalysts for alkaline OER.