Nanoscale palladium-Mo6S8/carbon nanowires toward efficient electrochemical hydrogen evolution and hydrogen peroxide detection

Chevrel phase (CP) molybdenum sulfides (Mo₆S₈) have attracted extensive research attention in the field of energy conversion and storage due to their unique electronic structures and rich open channels. However, comprehensive understanding of intrinsic kinetic mechanisms governing the electrocatalytic bi-functional hydrogen evolution reaction (HER) and hydrogen peroxide (H₂O₂) sensing on CP-based composites is still lacking. Herein, nanosized palladium (Pd) and Mo₆S₈ particles were assembled in carbon nanowires (C NWs) via electrospinning followed by pyrolysis. The as-obtained novel Pd-Mo₆S₈/C NWs exhibited excellent performance in terms of a low overpotential of −194 mV at η₁₀ for HER, and an ultrahigh sensitivity of 2231 μA mM⁻¹ cm⁻² with a limit of detection of 25 nM for H₂O₂ sensing. The experimental and theoretical findings demonstrated that Pd and Mo₆S₈ nanoparticles (NPs) exhibited exceptional catalytic activity and strong electronic interactions. The synergistic effects of these two components could effectively modulate the binding strength of reactants and intermediates on the catalyst surface, ultimately leading to improved electrochemical catalytic performance toward reduction of small molecules. Moreover, verification of the stable tolerance in various environments and good selectivity of the electrocatalyst promoted the further use of Pd-Mo₆S₈/C NWs-based electrochemical sensing system for sensing additional H₂O₂ in milk samples, proving the widespread potential of this material for practical applications. This study significantly advances the understanding of nanoscale and bi-functional CP-based composites.