Precision‐Engineered Electronic Modulation of Ruthenium Clusters and Single Atoms on Vacancy‐Rich α‐MoC _1‐ <i> _x </i> Enables Efficient Electrocatalytic Water Splitting

ABSTRACT 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 H 2 . 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 H 2 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–H 2 O batteries employing 3%‐Ru CS/SA /α‐MoC 1‐x /C as the cathode electrocatalyst exhibit exceptional performance.