Junshuang Zhou

Efficient alkaline hydrogen evolution requires rapid water dissociation and onward migration of adsorbed hydrogen (H*), yet coordinating these sequential processes across metal–support interfaces remains challenging. Here, Ru clusters are anchored on oxygen-vacancy-rich WO3-x nanoneedle arrays (Ru/RWO), with lower-vacancy Ru/PWO as a control. Experiments and density functional theory calculations reveal that vacancy enrichment coordinates support-side water activation and subsequent H* migration. Vacancy-adjacent undercoordinated W centers act as Lewis acid sites, promoting H2O adsorption and O–H bond cleavage. Meanwhile, the reduced work-function mismatch weakens net electron withdrawal from Ru and alleviates interfacial charge accumulation, thereby mitigating excessive H* stabilization at interfacial Ru and lowering the barrier for onward migration to an adjacent Ru site within the cluster from 0.32 to 0.23 eV. Ru/RWO requires only 22 and 61 mV to deliver 10 and 100 mA cm-2, respectively, with a Tafel slope of 34.2 mV dec-1 in 1.0 M KOH, and sustains 0.5 A cm-2 for 600 h. An anion-exchange-membrane water electrolyzer reaches 1.0 A cm-2 at 1.91 V and operates for 150 h. These findings provide a coupled structural and electronic regulation strategy for synchronizing intermediate generation and transfer in multistep electrocatalysis.

Cost-effective transition-metal catalysts are attractive for industrial alkaline water electrolysis, yet their oxophilicity often causes overly strong OH* adsorption that blocks active sites and suppresses continuous H2O activation and H* turnover. Here, we construct a Pt-centered functional microenvironment by anchoring platinum single atoms on nickel-molybdenum (PtSA/Ni4Mo) via a two-step electrodeposition process, which regulates OH* at the interface. Pt single-atom modification substantially enhances Ni4Mo, decreasing η10 to 19 mV and η500 to 137 mV (Ni4Mo: 51 and 268 mV), while maintaining an advantage over Pt/C at high current and delivering kinetics (28.9 mV dec-1). Furthermore, the catalyst enables an anion exchange membrane water electrolyzer (AEMWE) to reach 1 A cm-2 at 1.97 V with stable operation beyond 200 h. Integrated SCN- poisoning, in situ Raman, CV, and EIS analyses collectively identify that Pt single atoms accelerate OH clearance on the OH-affinitive Ni₄Mo surface, thereby restores interfacial sites for water activation and shifts the kinetics toward a Heyrovsky-limited pathway. Density functional theory (DFT) further confirms weakened OH adsorption near Pt and a dramatically reduced OH desorption barrier, rationalizing the accelerated alkaline HER kinetics. This work highlights single-atom micro-environment engineering as an effective route to suppress OH poisoning for industrially relevant alkaline HER.