Modulating dual-active sites within one ruthenium nanocluster by engineering electronic metal-support interactions for efficient hydrogen electro-oxidation

Designing non-Pt metal electrocatalysts for alkaline hydrogen oxidation reaction (HOR) is highly desirable to address the unsustainable use of high-cost and scarce Pt. Although challenging, this study introduces an ultrasmall Ruthenium nanoclusters (Ru NCs)-based electrocatalyst with dual active sites for efficient alkaline HOR. While the selection of Ru is based on its cost-effectiveness, smaller atomic number, and comparable physicochemical properties to Pt, the employment of Mo2C as the support is mainly for establishing strong electronic metal-support interaction (EMSI) within the catalyst. This EMSI effect facilitates significant charge redistribution and the formation of efficient dual-active sites within a single Ru NC. Experiments and simulations confirm that the EMSI effect modulates the d-band centers of the Ru NCs at both H-adsorption and OH-adsorption sites, endowing the Ru/Mo2C catalyst with up to 16.6 times and 29.7 times higher mass activity than commercial Pt/C and Ru/C, respectively, as well as enhanced long-term stability and CO resistance. This work provides a paradigm in designing non-Pt metal NCs for alkaline HOR electrocatalysis, underscoring the significance of adjusting the EMSI effect for performance escalation of HOR catalysis.