Growth of MoS₂ nanosheets on M@N-doped carbon particles (M = Co, Fe or CoFe Alloy) as an efficient electrocatalyst toward hydrogen evolution reaction

The design and synthesis of a highly active noble metal-free electrocatalyst for hydrogen evolution reaction (HER) from water splitting are crucial for renewable energy technologies. Herein, we report the growth of molybdenum disulfide (MoS₂) on N-doped carbon encapsulated metal particles (M@NDC@MoS₂, where M = Co, Fe or CoFe alloy) as a highly active electrocatalyst for HER. The hierarchical MoS₂ nanosheets are grown on M@NDC using the hydrothermal method. Our results show that CoFe@NDC@MoS₂ hybrid spheres exhibit excellent HER performance with an overpotential of 64 mV at a current density of 10 mA cm⁻² and a small Tafel slope of 45 mV dec^-1. In addition, CoFe@NDC@MoS₂ hybrid spheres have good long-term stability and durability in acidic conditions. Besides, density functional theory (DFT) simulations of the proposed catalysts are performed and suggest that the superior catalytic activity of CoFe@NDC@MoS₂ is due to the optimal electron transfer from CoFe@NDC nanoparticles to MoS₂ nanosheets. This electron transfer facilitates H⁺ interaction and adsorption, leading to a decreased Gibbs free energy (ΔG_H* ≈ 0.08 eV) and local work function on the surface, which consequently enhances the HER performance.