Seed-Induced Directional Growth of Ni-MOF-Derived Ni/NiO Heterogeneous Nanosheets for Efficient Hydrogen Evolution Reaction

Nickel-based catalysts demonstrate considerable promise for the hydrogen evolution reaction (HER), yet attaining both exceptional activity and sustained durability under prolonged operation persists as a critical research challenge. Herein, a directed self-growth strategy is employed to synthesize Ni-MOF nanosheets with a well-ordered morphology on the nickel foam (NF) surface via strong acid etching followed by ligand introduction. The dense Ni²⁺ layer generated by acid etching, as a seed, promotes strong bonding between the Ni-MOF and the NF substrate, which accelerates electron transport to the active layer and prevents catalyst detachment during long-term operation. Additionally, the Ni/NiO heterostructure obtained via pyrolysis forms an electron transfer channel that optimizes *H and *H₂O adsorption on the Ni side while facilitating *OH desorption through its migration to the NiO domain, collectively contributing to improved HER kinetics. In situ Raman spectra reveal the evolution of key intermediates during the HER, corroborating the DFT predictions and highlighting the critical role of interfacial H₂O structures in catalytic performance. The obtained S-Ni-MOF/NF-400 catalyst exhibits an ultralow overpotential (20 mV-10 mA cm^-2), surpassing commercial Pt/C catalysts. Moreover, long-term stability tests demonstrate significant improvements in durability. This work not only introduces an outstanding Ni-MOF-based catalyst but also presents a novel strategy for designing highly active and stable HER catalysts.