Hierarchical Mo6S8@MoS2/carbon nanowires toward efficient electrochemical hydrogen evolution

Chevrel phase molybdenum sulfides (CP-Mo 6 S 8 ) have attracted considerable attention in catalysis and energy conversion owing to their unique electronic structures, open-framework channels, and remarkable electrochemical properties. Nevertheless, their practical implementation in the electrochemical hydrogen evolution reaction (HER) is significantly constrained by surface oxidation, which leads to diminished catalytic activity. To address this challenge, hierarchical Mo 6 S 8 @MoS 2 /carbon nanowires (C NWs) were designed in this study via a scalable electrospinning strategy combined with subsequent pyrolysis and in-situ vulcanization. The resulting nanostructure features Mo 6 S 8 nanoparticles encapsulated within rich MoS 2 nanosheets, which are supported by carbon nanowires. This architecture ensures the full functional expression of two types of molybdenum sulfides during catalysis while effectively preventing the surface oxidation of Mo 6 S 8 in air. Benefiting from this core-shell synergy, the optimized 250-Mo 6 S 8 @MoS 2 /C NWs exhibit outstanding HER performance, with a low overpotential of 181 mV at 10 mA cm −2 and a small Tafel slope of 37 mV dec −1 . Density functional theory (DFT) calculations reveal that the Mo 6 S 8 @MoS 2 heterostructure enables pronounced electronic interactions and an optimal hydrogen adsorption Gibbs free energy (ΔG H* ), explaining its excellent HER performance. This work establishes controlled oxidation and vulcanization as an effective route to efficient and robust electrocatalysts, opening new avenues for the development of cost-effective materials for energy applications. Graphic abstract