Iron‐incorporated Ni₄Mo Hierarchical Nanorod Arrays for Promoted Electrocatalytic Oxygen Evolution Reaction

Abstract

It is great significance to explore rich and efficient transition metal‐based electrocatalysts for the electrolysis of water. Nickel‐molybdenum (Ni−Mo) alloy is considering as one of the most promising electrocatalysts for hydrogen evolution reactions (HER) in alkaline electrolyte, but its catalytic performance for oxygen evolution reaction (OER) is still unsatisfactory. Heteroatom doping by interfering with the electronic structure of the catalysts has been considered to be an effective method to enhance electrocatalytic activities. Herein, we report the synthesis of iron (Fe)‐doped Ni4Mo intermetallic compound with hierarchical nanorod assemblies on nickel foam by hydrothermal and hydrogen‐induced methods, which significantly improve the catalytic performance for OER. The as‐prepared Fe−Ni4Mo/NF shows remarkable activity for alkaline oxygen evolution reaction, requiring only a low overpotential of 271 mV to achieve a current density of 100 mA cm−2. Such performance is significantly better than that of pristine Ni4Mo/NF with overpotential of 400 mV. Density functional theory (DFT) calculation shows that the addition of Fe can significantly reduce the adsorption energy of the intermediate on the catalyst surface, thus facilitating the OER activity. Moreover, an alkaline electrolyzer composed of Fe−Ni4Mo/NF as cathode and anode can provide 10 mA cm−2 current density with only 1.48 V extremely low voltage, and shows excellent long‐term durability of 24 h. These results highlight a heteroatom incorporation engineering strategy into metallic alloys for electrochemical applications.