RuNi bimetallic nanoclusters anchored on hollow mesoporous carbon: Ru-O-Ni bridge modulated superior alkaline hydrogen evolution performance

RuNi nanoclusters confined in hollow mesoporous carbon are synthesized by a template-impregnation method. • RuNi/MCS-3 delivers superior alkaline HER performance comparable to commercial Pt/C. • Formed Ru−O−Ni bridge accelerates water dissociation and optimizes H* adsorption. • Pore confinement and electronic synergy offer a strategy for advanced HER electrocatalysts. Developing efficient and stable bimetallic electrocatalysts for the hydrogen evolution reaction (HER) in alkaline media is crucial for sustainable water splitting. However, this field still faces substantial challenges. Herein, a series of hollow mesoporous carbon-confined RuNi bimetallic nanocluster catalysts (RuNi/MCS-x) were synthesized via a facile combination of the template method and impregnation strategy. Their electrocatalytic HER performance was systematically evaluated in 1 M KOH solution. Notably, the MCS-3 material, prepared at a TPOS/TEOS volume ratio of 1:1, exhibits an optimal porous structure with a large pore size of 5.64 nm and a high specific surface area of 631.34 m 2 g −1 . The interconnected porous structure, linking the internal hollow cavities to the outer surface, provides sufficient transport channels for electrolyte penetration and hydrogen release. Benefiting from these structural advantages, the RuNi/MCS-3 catalyst delivers excellent alkaline HER performance. It requires only an overpotential of 15.6 mV to achieve a current density of 10 mA cm −2 in 1 M KOH electrolyte and displays a high mass activity of 651.4 mA mg Ru −1 at an overpotential of −50 mV. In addition, RuNi/MCS-3 achieves a Faradaic efficiency (FE) close to 100%, and its turnover frequency (TOF) is comparable to that of commercial Pt/C catalysts. The superior catalytic activity originates from three synergistic factors. First, the unique Ru−O−Ni bridging structure creates abundant electron-rich oxygen sites to promote water dissociation, optimize H* adsorption, and accelerate hydrogen desorption kinetics. Second, the pore confinement of hollow mesoporous carbon facilitates uniform dispersion of RuNi nanoclusters and full exposure of active sites. Third, the Ru−O−Ni bridge facilitates electron transfer and lowers the kinetic barrier of the alkaline HER, thereby substantially boosting the overall water-splitting efficiency. This work presents a feasible innovative strategy to rationally design and fabricate high-efficiency bimetallic carbon electrocatalysts toward high-performance HER. Download: Download high-res image (142KB) Download: Download full-size image The mesoporous carbon-confined RuNi bimetallic nanoclusters (RuNi/MCS-3) construct interfacial Ru–O–Ni bridges, which induce electron redistribution and trigger hydrogen spillover to optimize hydrogen adsorption/desorption kinetics. Benefiting from the interfacial synergistic effect, RuNi/MCS-3 exhibits substantially enhanced electrocatalytic hydrogen evolution activity compared with monometallic Ru/MCS-3.