Magnetic Free‐Standing Electrodes Achieving Efficient Oxygen Evolution Reaction via Electronic Structure Regulation

ABSTRACT The sluggish kinetics of the multiple‐electron/proton oxygen evolution reaction (OER) remain a major bottleneck for alkaline water electrolysis. Modulating the electronic structure of catalysts is thus crucial for developing OER electrodes with superior activity and durability. Herein, we report a simple two‐step strategy to construct a magnetic free‐standing FeNiCoSe ₂ /Ni ₃ Se ₄ electrode, in which Fe doping effectively tailors the electronic spin structure of metal active sites, leading to remarkable OER activity. Specifically, the FeNiCoSe ₂ /Ni ₃ Se ₄ electrode delivers a low overpotential of 278 mV at 100 mA cm ⁻² and a small Tafel slope of 47.0 mV dec ⁻¹ in 1.0 m KOH. Remarkably, it maintains stable operation for over 900 h at 5000 A m ⁻² under high‐temperature and concentrated alkaline conditions, demonstrating exceptional durability and practical feasibility for industrial water electrolysis. Such superior performance originates from the high‐spin state of in situ formed metal (oxy)hydroxide active phase, which synergistically optimizes the adsorption‐desorption balance and electron transfer processes. This work offers a mechanistic investigation for regulating electronic spin structures via a doping strategy, paving the way for electronic‐engineered free‐standing electrodes toward industrial water electrolysis.