Iron-Doped Nickel Cobalt Phosphide Nanoarrays with Urchin-like Structures as High-Performance Electrocatalysts for Oxygen Evolution Reaction

It is challenging to explore non-noble metal-based electrocatalysts with high-performance and long-term stability for oxygen evolution reaction (OER). Herein, urchin-like iron-doped nickel cobalt phosphide (FeNiCoP) with hierarchical nanoarray structures and fine-tuned doped Fe content is fabricated through a simple hydrothermal method and subsequent phosphorization process. The optimized FeNiCoP manifests outstanding OER electrocatalytic performance in an alkaline electrolyte with a low overpotential of 259 mV at 10 mA·cm–2 and a Tafel slope of 40 mV·dec–1, which is superior to the benchmark IrO2 and nickel cobalt phosphide (NiCoP) catalysts. The electrochemical activity of NiCoP can be improved by regulating the content of doped Fe. The enhanced catalytic performance of FeNiCoP can be ascribed to the unique urchin-like structure and electronic interaction among Fe, Ni, and Co elements, which expose more active sites, facilitate ion diffusion and gas release, optimize the electronic structure, and thereby enhance OER catalytic performances. Above all, these indicate that the as-prepared FeNiCoP with excellent activity and stability may be a good alternative to commercial precious metal-based catalysts.