Iron‐Doped Nickel Phosphide Nanosheets In Situ Grown on Nickel Submicrowires as Efficient Electrocatalysts for Oxygen Evolution Reaction

Abstract

Abstract Tens of micrometers long metallic Ni submicrowires with a diameter of approximately 200 nm are prepared by a chemical reduction method under a magnetic field. Fe‐doped Ni 2 P nanosheets are then in situ grown on Ni submicrowires by a simple wet‐chemical reaction followed by a low‐temperature phosphorization process. The (Ni 0.87 Fe 0.13 ) 2 P–Ni composite exhibits the highest catalytic activity toward oxygen evolution reaction in alkaline solution among all the as‐prepared (Ni 1− x Fe x ) 2 P–Ni catalysts, delivering a current density of 10 mA cm −2 at an overpotential of only 257 mV and keeping high stability over 10 h electrolysis. These exceptional activities are attributed to the unique structure combining metallic Ni submicrowires as good electronically conductive substrate and the in situ grown Fe‐doped Ni 2 P nanosheets. Specifically, Fe incorporation leads to strong electron interactions between Ni, Fe, and P, fast reaction kinetics, small charge‐transfer resistance, and a large electrochemical surface area, which are responsible for the excellent catalytic performance.