FeNi@N-Doped Graphene Core–Shell Nanoparticles on Carbon Matrix Coupled with MoS₂ Nanosheets as a Competent Electrocatalyst for Efficient Hydrogen Evolution Reaction

Synthesis of noble-metal-free electrocatalysts for green hydrogen production is crucial to overcoming the energy demand of modern society. One of the most competitive and alternative noble-metal-free electrocatalysts for hydrogen evolution reaction (HER) is molybdenum disulfide (MoS₂)-based composites. Herein, it is shown that MoS₂ nanosheets grow on FeNi@N-doped graphene nanoparticles/N-doped carbon matrix (FeNi@NG/NCM@MoS₂), using the hydrothermal method. FeNi@NG/NCM@MoS₂ hybrid displays outstanding HER performance with a low overpotential of 79 mV at 10 mA cm⁻², a small Tafel slope of 40.2 mV dec⁻¹, and high durability. First-principles density functional theory simulations confirm the electron transformation from FeNi alloy to NG surface of FeNi@NG particle and subsequently further transfer to MoS₂ nanosheets, which decrease the Gibbs free energy (ΔG_H* ≈ −0.08 eV) and local work function for enhanced HER activities. This work highlights the understanding of electron transfer in demonstrating the kinetic reaction of the HER process and offers a new avenue for constructing efficient MoS₂-based electrocatalysts.