Interfacial water reconfiguration driven by dual-site synergism in Pt/MoC toward efficient alkaline hydrogen evolution.

Alkaline hydrogen evolution reaction (HER) is central to practical water electrolysis while the kinetics are largely limited by sluggish water dissociation, hydroxide-induced interfacial passivation, and inefficient H* conversion, especially on Pt-based catalysts with limited atomic utilization. Herein, we report a low-Pt-loading (1.99 wt%) dual-site catalyst composed of Pt species and MoC nanoparticles embedded within a nitrogen-doped carbon framework (denoted as Pt/MoC@NC). The adjacent Pt/MoC interface integrates MoC-assisted H2O activation with Pt-mediated H conversion, thereby accelerating alkaline HER kinetics. Electrochemical analyses and operando spectroscopy establish that the enhanced activity originates from the synergism from Pt/MoC dual-site interface, where electronically modulated Pt centers facilitate the H* conversion, while adjacent MoC promotes the water activation, thus enriching the ratio of reactive K+-H2O. This coupled interfacial regulation reconstructs the local water network, which further favors H-OH bond cleavage, to lower the apparent HER activation energy. Benefitting from the dual-site synthetic effect, Pt/MoC@NC delivers the low overpotential of only 14 mV at 10 mA cm-2 with a Tafel slope of 35.8 mV dec-1, outperforming commercial Pt/C and counterparts. This work establishes dual-site cooperativity coupled with interfacial water reconfiguration as an effective strategy for designing low-Pt-loading alkaline HER electrocatalysts.