Enhancing hydrogen oxidation electrocatalysis of nickel-based catalyst by simultaneous chemical anchoring and electronic structure regulation

Designing electrocatalysts for hydrogen oxidation reaction (HOR) in alkaline media is crucial but challenging. Among all available electrocatalysts, Ni-based materials are recognized as the most potential precious-metal-free electrocatalysts for HOR. However, they still suffer from serious problems including low activity and poor stability. In this work, a synergistic chemical anchoring and electronic structure regulation strategy is proposed to gain both high electrocatalytic activity and stability for Ni-based HOR catalyst. N-doped graphite nanoflakes (N-GFs) support with abundant N anchoring sites can stabilize the loading of Ni-based active species, giving rise to an excellent stability of the catalyst. Meanwhile, the rationally designed heterostructure in the active Ni 3 N/Ni can trigger the electron transfer across the heterointerface, which optimizes the binding energy of the reaction intermediates, resulting in an accelerated the Volmer reaction. Benefited from the rational design, Ni 3 N/Ni/N-GFs exhibits excellent mass activity (42.7 A g Ni -1 at the overpotential of 50 mV) and stability (more than 24 h continuous operation). Moreover, the Ni 3 N/Ni heterostructure performs better in HOR electrocatalysis than individual Ni or Ni 3 N. These experimental results are rationalized by the theoretical simulations, which demonstrate that the heterostructure effectively weakens the hydrogen adsorption, optimizes the hydroxyl adsorption, and decreases the water formation reaction barrier.