Ru atom-modified Co₄N-CoF₂ heterojunction catalyst for high-performance alkaline hydrogen evolution

D-band-center control engineering, particularly combining both cation and anion intercalations towards heterostructure formation with simultaneous usage of Ru, N as well as F species, for optimal electronic structure as efficient hydrogen evolution reaction (HER) catalysts remains a daunting challenge but critical for renewable-energy technologies. Herein, we lay emphasis on the design of active-site electronic structure based on d-band-center shift through the construction of Co₄N-CoF₂ heterostructure coupled with Ru doping (Ru/Co₄N-CoF₂). Solvothermal coordination reaction followed by annealing course causes cooccurrence of F, N, Ru in Co neighborhood. As-obtained Ru/Co₄N-CoF₂ exhibits superior HER activity in alkaline electrolyte with overpotential as low as 53 mV to yield a current density of 10 mA cm⁻² which is close to that of commercial Pt/C, outperforming many transition-metal-based catalysts recent-reported. Moreover, it still presents good durability with continuous operation of 22 h in 1.0 M KOH. Such excellent performance is ascribed to appropriate electron structure of Ru/Co₄N-CoF₂ for optimized hydrogen binding abilities on Co/Ru sites as confirmed by synchrotron-based X-ray adsorption near-edge structure and X-ray photoelectron spectroscopies. This study not only establishes highly active electrocatalysts by impacting d-band center of active sites but also provides valuable insights into the synergistic-effect protocol of doping and heterostructure strategies for d-band-center shifting.