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

Chevrel phase (CP) molybdenum sulfides (Mo 6 S 8 ) 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 (H 2 O 2 ) sensing on CP-based composites is still lacking. Herein, nanosized palladium (Pd) and Mo 6 S 8 particles were assembled in carbon nanowires (C NWs) via electrospinning followed by pyrolysis. The as-obtained novel Pd-Mo 6 S 8 /C NWs exhibited excellent performance in terms of a low overpotential of −194 mV at η 10 for HER, and an ultrahigh sensitivity of 2231 μA mM −1  cm −2 with a limit of detection of 25 nM for H 2 O 2 sensing. The experimental and theoretical findings demonstrated that Pd and Mo 6 S 8 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-Mo 6 S 8 /C NWs-based electrochemical sensing system for sensing additional H 2 O 2 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.