Amorphous Fe(OH)_x‐NiCoP Heterostructures for Efficient Oxygen Evolution

ABSTRACT Achieving carbon peak and carbon neutrality goals has driven the development of the hydrogen energy industry, with water electrolysis being a key source of clean hydrogen. However, the slow kinetics of oxygen evolution reaction (OER) at the anode, especially under high current densities, hinders industrial‐scale water electrolysis for hydrogen production. The design and fabrication of non‐precious metal electrocatalysts with high OER activity at high current densities remain challenging. In this study, we synthesized an Fe(OH) x ‐NiCoP OER catalyst by electrodepositing amorphous Fe(OH) x onto low‐crystallinity phosphides, forming crystalline‐amorphous interface nanoneedle arrays. Characterization results revealed that the crystalline‐amorphous interfaces shortened ion/electron diffusion paths during electrochemical reactions and protected phosphides from corrosion. The incorporation of Fe enhanced the material's conductivity, while the sea urchin‐like clustered structure provided a high specific surface area and rough surface. Critically, the superhydrophilic nature of the catalyst facilitated rapid bubble detachment and enhanced electrolyte accessibility, which are pivotal for sustaining high‐current‐density operation. The Fe(OH) x ‐NiCoP/NF catalyst exhibited excellent electrocatalytic activity for OER in alkaline solution, demonstrating an overpotential of 357 mV at an industrially relevant current density of 1000 mA cm −2 and sustained catalytic activity for 750 h. Surface reconstruction of Fe(OH) x ‐NiCoP/NF during OER contributed to the improved electrochemical performance. This work underscores the synergistic role of superhydrophilicity and efficient gas release in achieving durable high‐current OER performance. By integrating crystalline and amorphous active sites into a multi‐component material system, this study offers a novel design strategy for efficient OER electrocatalysts under demanding industrial conditions.