Engineering Amorphous Structures in NiFe Alloys via Polymer Stabilization for Enhanced Oxygen Evolution Reaction Efficiency

Amorphous transition metal alloys are recognized as promising electrocatalysts for the oxygen evolution reaction (OER) owing to their structural disorder, abundant unsaturated coordination sites, and isotropically distributed active centers. However, achieving a high degree of amorphization remains a significant challenge. Herein, a highly amorphous NiFe alloy (Ni3Fe1B-PVP) catalyst is synthesized by a one-step liquid-phase reduction method using polyvinylpyrrolidone (PVP) as a polymer stabilizer. Notably, the introduction of PVP reduces the size of the nanoparticles and enhances the degree of amorphousness, endowing Ni3Fe1B-PVP with a larger specific surface area and abundant defects. Meanwhile, PVP may participate in the catalyst preparation process, regulating the electronic structures of Ni and Fe and promoting electron enrichment around the Ni centers, thereby enhancing the electronic conductivity and reaction kinetics. Consequently, Ni3Fe1B-PVP delivers remarkably low overpotentials of 240 and 320 mV at 10 and 50 mA cm–2, respectively, outperforming both its low-amorphous counterpart (Ni3Fe1B) and crystalline derivative (Ni3Fe1B-800), as well as benchmark IrO2 and RuO2. This work demonstrates that polymer-assisted synthesis is a powerful route to control the degree of amorphization in nonnoble metal electrocatalysts, providing guidance for the development of superior OER electrocatalysts.