Understanding the Atomic and Defective Interface Effect on Ruthenium Clusters for the Hydrogen Evolution Reaction

Water electrolysis powered by renewable electric energy is a promising technology for green hydrogen production without carbon emissions, while highly efficient and cost-effective electrocatalysts with long durability are urgently needed. Here, we demonstrate oxygen-coordinated single-atom iron sites (Fe–O₄) decorated carbon nanotubes with abundant vacancies as the substrate for stabilizing Ru clusters (CNT–V–Fe–Ru). The catalyst shows high performance for the hydrogen evolution reaction (HER) in both acidic and alkaline media, respectively. The HER kinetics analysis demonstrates that the defective substrate with single-atomic sites could significantly improve the intrinsic activity of Ru species. Theoretical calculations also support the superior HER behavior of CNT–V–Fe–Ru with fundamental insights into metal–substrate interactions. The present study highlights a unique feature of single-atom catalysts for serving as advanced supporting materials, which offers tremendous opportunities to adequately regulate electronic structures of metal–substrate interfaces at the atomic level.