Boosting Reaction Kinetics through the Construction of Ni₃S₂–MoS₂ Semicoherent Interfaces for Enhanced Electrochemical Overall Water Splitting

In recent years, the technology of electrocatalytic water splitting for hydrogen production has garnered significant interest. Nonetheless, the kinetics associated with the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are comparatively sluggish, thereby constraining the enhancement of water decomposition efficiency to a certain degree. In this paper, the Ni3S2-MoS2/ NF semicoherent heterostructure interface electrocatalyst with multistage nanosheet was synthesized by the hydrothermal method. At the material level, the structure adeptly incorporates a semicoherent interface with a multilayer nanosheet configuration. This design not only preserves the nanosheet morphology of the precursor but also facilitates the formation of folded nanoflowers, thereby increasing the active surface area and promoting the rapid transfer of electrons. Furthermore, it optimizes the electronic environment of the electrode through interface charge redistribution, thereby diminishing the adsorption of H by the strong S–H bonds and accelerating the reaction kinetics. Additionally, the structure achieves optimal lattice matching, which enhances ion diffusion and reduces the associated diffusion barrier. In a 1.0 M KOH solution, the catalyst showed excellent performance in both the OER and HER. In situ Raman spectroscopy demonstrated that Ni–OOH serves as the true active site for the OER. This study provides a new idea for the precise design of bifunctional HER and OER electrocatalysts.