Charge-counterbalance modulated amorphous nickel oxide for efficient alkaline hydrogen and oxygen evolution

Nickel oxides have been extensively explored as electrocatalysts for hydrogen and oxygen evolution in water splitting, of which the 3d8 electron and the partly occupied 3d orbitals configuration are modulable, but the catalytic activity is still far from expected. Herein, we report a charge-counterbalance strategy to engineer the 3d electronic structure by constructing unique chemical environmental, in which alkaline-earth metal (Sr, 4p6), electron-deficiency nonmetal (B, 2p1) and early-transition metal (V, 3d3) were synergistically combined. We confirm both experimentally and theoretically that the charge-counterbalance effect is critical, by which nickel shows optimized adsorption strength for the key reaction intermediates and promote the charge transfer in the electrochemical reactions. Consequently, the as-obtained SrVB-NiO catalyst demonstrates impressive HER and OER activities, along with remarkable long-term stability in alkaline solution. This work shed light on a new approach for the further design of electrocatalysts.