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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. [ABSTRACT FROM AUTHOR]

Developing low‐cost and high‐efficient bifunctional catalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is greatly significant for water electrolysis. Here, Ni3N‐CeO2/NF heterostructure is synthesized on the nickel foam, and it exhibits excellent HER and OER performance. As a result, the water electrolyzer based on Ni3N‐CeO2/NF bifunctional catalyst only needs 1.515 V@10 mA cm−2, significantly better than that of Pt/C||IrO2 catalysts. In situ characterizations unveil that CeO2 plays completely different roles in HER and OER processes. In situ infrared spectroscopy and density functional theory calculations indicate that the introduction of CeO2 can optimizes the structure of interface water, and the synergistic effect of Ni3N and CeO2 improve the HER activity significantly, while the in situ Raman spectra reveal that CeO2 accelerates the reconstruction of OV (oxygen vacancy)‐rich NiOOH for boosting OER. This study clearly unlocks the different catalytic mechanisms of CeO2 for boosting the HER and OER activity of Ni3N for water splitting, which provides the useful guidance for designing the high‐performance bifunctional catalysts for water splitting. [ABSTRACT FROM AUTHOR]