Synergistically modulating d-band centers of bimetallic elements for activating cobalt atoms and promoting water dissociation toward accelerating alkaline hydrogen evolution

It is of great significance to synergistically modulate d-band centers (εd) of multiple transition metals (TMs) for designing and developing highly efficient hybridized-electrocatalysts. Herein, the downshift in Co εd is realized by synthesizing Co single atoms with low nitrogen-coordination number (CoN2) at high T during the pyrolysis step while upshifting Ru εd is achieved via decreasing Ru precursor mass to anchor Ru nanoclusters instead of nanoparticles on CoN2−containing carbon substrates (CoN2/Ru−NC). In our strategy, the downshift in Co εd leads to a favorable affinity between Co sites of CoN2/Ru−NC and H⁎ for desorption of H2; additionally, upshifting Ru εd helps the adsorption of OH⁎ intermediates on Ru nanoclusters for CoN2/Ru−NC to promote water dissociation toward accelerating alkaline producing H2. In consequence, CoN2/Ru−NC demonstrates an outstanding activity with an ultralow overpotential of ∼ 9.0 mV at 10.0 mA cm-2, which suppresses activities of Pt/C (24.0 mV) and most previously-reported Ru-based electrocatalysts.