Dynamic Self‐Reconstruction Heterostructures: Boosting the High‐Stability for Hydrogen Evolution of NiMo Alloys in Acidic Environments

Abstract Electrocatalytic water splitting is considered one of the most promising approaches for large‐scale hydrogen production. However, designing transition metal catalysts with high durability under acidic conditions remains a significant challenge. The durability of the catalyst is closely related to the changes of the catalyst during its operation, and constructing effective surface reconstruction strategies can help address the durability issues of transition metals in acidic hydrogen evolution reactions (HER). Herein, the spontaneous formation of surface‐reconstructed heterostructures of NiMo alloys is reported during the HER in acidic media. The surface of the catalyst is characterized by the presence of Ni/Mo metal nanoparticles and Ni _x Mo _y O _z nanosheets, which coexist as HER proceeds. Notably, the E‐Ni ₉₀ Mo ₁₀ /CC After 96 h catalyst demonstrates a significantly reduced overpotential of 56.84 mV at 10 mA cm⁻ ² in 0.5 m sulfuric acid, which is better than other E‐Ni ₉₀ Mo ₁₀ /CC counterparts. Both experimental data and theoretical calculations suggest that these spontaneously formed heterostructures are helpful for optimizing hydrogen adsorption. Furthermore, the downward shift of the d‐band center within the heterostructure (Ni ₉₀ Mo ₁₀ /Ni _x Mo _y O _z ) is found to facilitate the desorption of intermediate products, thereby enhancing the overall HER activity. This work provides a new perspective for designing highly durable transition metal catalysts for acidic HER.