Local Electronic Environment Regulation of Crystalline/Amorphous NiSe/NiFe(OH) _x Heterostructure Enhancing Catalytic Activity of Alkaline Oxygen Evolution Reaction

ABSTRACT Designing heterostructure catalysts with unique interface effects is an effective method for enhancing the activity and stability of the oxygen evolution reaction (OER), which is crucial for advancing large‐scale hydrogen production through water electrolysis. Here, a crystalline NiSe/amorphous NiFe(OH) _x (c‐NiSe/a‐NiFe(OH) _x ) heterostructure catalyst was constructed via a two‐step hydrothermal‐solvent thermal method. Benefiting from the engineered local environment, unique dynamic crystalline–amorphous interfaces, and the charge redistribution, the catalyst exhibits outstanding performance with an ultralow overpotential of 233 mV at 100 mA cm ⁻² . After the stability test for 250 h at a current density of 500 mA cm ⁻² , it retains 93.7% of its initial activity. Density functional theory (DFT) calculations suggest that interfacial electronic modulation optimizes the adsorption energy of the key intermediate *O, thereby accelerating the OER kinetics. This work provides a new design strategy for constructing crystalline–amorphous heterostructure catalysts with both excellent catalytic activity and stability.