Facile fabrication of a hierarchical NiCoFeP hollow nanoprism for efficient oxygen evolution in the Zn–air battery

Abstract

The rational construction of the chemical composition and morphological structure of electrocatalysts has been considered as the key to their electrochemical performance and energy storage. Herein, we report the facile fabrication of the hierarchical Ni₂P–Co₂P–Fe₂P hybrid hollow nanoprism (abbreviated as NiCoFeP-HN), which could efficiently work as the oxygen evolution reaction (OER) electrocatalyst in the rechargeable Zn–air battery. NiCoFeP-HN was synthesized via an in situ ion exchange reaction of nickel–cobalt precursors with [Fe(CN)₆]³⁻ at room temperature and the subsequent phosphorization at 300 °C under N₂. The ion exchange procedure was crucial for preserving the nanoprism morphology and enhancing the OER performance. NiCoFeP-HN exhibited satisfactory activity with a small overpotential of 294 mV at 10 mA cm⁻² and remarkable stability for over 12 h. Compared to the conventional RuO₂ + Pt/C Zn–air battery, the NiCoFeP-HN + Pt/C based Zn–air battery has exhibited superior energy density and much better cycling stability. This work presents a facile and efficient avenue for the construction of hollow nanostructures and hybrid compositions, and provides a promising candidate with good electrochemical performance and energy storage.