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

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 (∆G_H*). 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.