Zipper‐Like Interlocked Heterostructure of NiFe Layered Double Hydroxide‐WN for Super‐Stable Oxygen Evolution over 4500 h

Abstract

The nickel‐iron based materials are widely studied as excellent oxygen evolution reaction (OER) electrocatalysts. However, its relatively poor OER stability limits its practical applications. Herein, a zipper‐like interlocked heterostructure of NiFe layered double hydroxide (LDH)‐WN is constructed. The NiFe LDH‐WN exhibits not only ultrahigh OER activity of 228 mV overpotential at a current density of 50 mA cm−2, but also extremely long‐term stability over 4500 h at 50 mA cm−2 and over 550 h at an industrial current density ≈350 mA cm−2, which is ascribed to its special zipper‐like interlocked structure. Moreover, in situ Raman confirms that the presence of WN can efficiently achieve NiFe LDH reconstruction to slower the metal dissolution during OER, and therefore boosts its stability. DFT calculations reveal that WN not only can increase the *O adsorption capability and conductivity of NiFe LDH layer, but also can anchor the metal atoms of NiFe LDH layer to improve the dissolution energy barrier. In short, this work presents a new method of constructing the interlocked heterostructure to improve the OER stability of Ni‐Fe‐based catalysts, which would accelerate its practical application.