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It is of great significance to synergistically modulate d -band centers (ε d) of multiple transition metals (TMs) for designing and developing highly efficient hybridized-electrocatalysts. Herein, the downshift in Co ε d is realized by synthesizing Co single atoms with low nitrogen-coordination number (CoN 2) at high T during the pyrolysis step while upshifting Ru ε d is achieved via decreasing Ru precursor mass to anchor Ru nanoclusters instead of nanoparticles on CoN 2 −containing carbon substrates (CoN 2 /Ru−NC). In our strategy, the downshift in Co ε d leads to a favorable affinity between Co sites of CoN 2 /Ru−NC and H* for desorption of H 2 ; additionally, upshifting Ru ε d helps the adsorption of OH* intermediates on Ru nanoclusters for CoN 2 /Ru−NC to promote water dissociation toward accelerating alkaline producing H 2. In consequence, CoN 2 /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. [Display omitted] • Our strategy anchors Ru nanoclusters on CoN 2 −containing carbon substrates. • Downshifting Co d -band center (ε d) activates Co atoms as catalytical sites. • Upshifting Ru ε d promotes H 2 O dissociation on Ru nanoclusters for alkaline HER. • This work provides a new way to design efficient electrocatalyst by modulating ε d. [ABSTRACT FROM AUTHOR]

This study reveals how the textural properties of hierarchically porous group V b metal oxides, prepared via a spontaneous auto-formation process, can strongly depend upon the pH of the reaction media, with an acidic media increasing the specific surface of Nb 2 O 5 whereas a basic medium results in the highest specific surface for Ta 2 O 5 . Catalytic oxidation of toluene over Pd loaded hierarchically porous group V b systems, and the supports alone, has shown that supports synthesised at pH 6 are the most active, despite having lower specific surfaces, thus implying modifications to the surface chemistry in the presence of H + or OH − can affect the overall performance of the supported catalytic system. [ABSTRACT FROM AUTHOR]