Electronic Structure Modulation of Ni2P Nanospheres via Interfacial Control With Lattice-Expanded MoS2 Nanosheets for Enhanced Hydrogen Evolution.

The development of cost-effective and durable electrocatalysts is a prerequisite for scalable hydrogen production via water electrolysis. In this context, modulating the electronic structure of transition-metal phosphide electrocatalysts via interfacial engineering with transition-metal chalcogenides has emerged as a compelling strategy to accelerate the hydrogen evolution reaction. Herein, we report an ultrasonication-assisted synthesis of ultrathin sub-20-nm MoS2 intimately integrated with Ni2P nanoparticles (R-MoS2@Ni2P). In R-MoS2@Ni2P, the unique heterointerface configuration induces a bending-induced lattice expansion in ultrathin MoS2 and modulates the electronic structure of Ni2P, facilitating interfacial charge redistribution for efficient HER. XPS analysis reveals that electrons are partially transferred from Ni2P to ultrathin MoS2. Furthermore, density functional theory calculations revealed that tensile strain in the O-MoS2 results in a downshift of the d-band center and an optimized hydrogen adsorption free energy (∆GH*). Consequently, the as-prepared R-MoS2@Ni2P exhibits significantly enhanced HER activity and long-term stability in both half-cell measurements and a PEMWE system compared with pristine Ni2P. This study demonstrates that interfacial engineering with ultrathin MoS2 nanosheets is an effective strategy to optimize the electronic properties of active Ni2P species, offering a promising design framework for advanced energy-conversion catalysts.