Precision-Engineered Electronic Modulation of Ruthenium Clusters and Single Atoms on Vacancy-Rich α-MoC_{1- x} Enables...

Maximizing the utilization of active metals while maintaining efficient catalytic activity is of great importance for electrocatalytic alkaline hydrogen evolution reaction. Herein, we report a facile pyrolysis strategy to anchor Ru clusters and adjacent Ru single atoms on α-MoC_1-x coated carbon nanospheres (termed as Ru_CS/SA/α-MoC_1-x/C). Theoretical calculations combined with in situ characterizations reveal that an electron-bridging mechanism whereby Ru single atoms donate electrons to the defective α-MoC_{1- x}, which subsequently transfers electron to Ru clusters, enabling a cooperative modulation of the electronic structure across different types of Ru sites. Therefore, the dual excitation of Ru single atoms and α-MoC_1-x weakens the binding strength between Ru clusters and H*, accelerates the desorption of H₂. The as-obtained 3%-Ru_CS/SA/α-MoC_1-x/C sample attains an excellent overpotential of 9 mV at 10 mA cm^-2 along with a mass activity of 20.38 A mg^-1 _Ru (-100 mV) and a turnover frequency of 1.71 H₂ s^-1 at 25 mV, which is larger than those of 20% Pt/C. Moreover, Both the anion exchange membrane water electrolysis cells and Zn-H₂O batteries employing 3%-Ru_CS/SA/α-MoC_1-x/C as the cathode electrocatalyst exhibit exceptional performance.