Achieving efficient alkaline hydrogen evolution reaction on long-range Ni sites in Ru clusters-immobilized Ni3N array catalyst.

[Display omitted] • Ru clusters are immobilized on hierachical Ni 3 N arrays. • The interfacial Ru atoms enable long-range Ni atoms as active sites via electron delocalization. • The H 2 O and H* adsorption energies are strengthened and weakened, respectively. • An outperforming Pt/C benchmark activity is achieved at ≥ 125 mA cm−2. Hydrogen (H 2) production from alkaline water electrocatalysis is economically appealing yet significantly hindered by the sluggish H 2 O adsorption and H* binding kinetics on active sites during hydrogen evolution reaction (HER). Herein, we interfacially immobilize Ru clusters on the hierarchical nickel nitride (Ru-Ni 3 N) nanosheet arrays via the filling of Ru3+ species into the metal vacancies of nickel hydroxide precursors and the subsequent controllable nitridation. The optimized Ru-Ni 3 N shows the outstanding HER performance, affording a 30-fold rise in the intrinsic activity of Ni sites, a outperforming-Pt/C overpotential at ≥ 125 mA cm−2 while remaining a robust stability. We further establish by a combined study of density functional theory (DFT) calculations with experimental analyses that long-range Ni sites around Ru sites act as active sites via the electron delocalization, remarkably weakening the H 2 O adsorption and H* binding barriers for enhancing the alkaline HER kinetics. Moreover, it also demonstrates an excellent pH-universal HER and overall water splitting performance. [ABSTRACT FROM AUTHOR]