Surface-Reconstructed Oxygen-Vacancy-Rich Amorphous-Crystalline Ni(Co) Heterostructure for Boosted Oxygen Evolution Reaction

The design of low-cost and robust electrocatalysts with rich active sites remains challenging for improving the efficiency of water oxidation. Herein, ternary Ni-Co-Mo oxide films were uniformly synthesized on Cu foil via simple electrochemical deposition method. After surface reconstruction, the robust amorphous-crystalline amorphous-crystalline Ni(Co) heterostructure with rich oxygen vacancies were achieved. Accordingly, the as-obtained surface-reconstructed heterostructure catalysts exhibited a superior oxygen evolution reaction activity with overpotential as low as 308 mV at 20 mA/cm² and a small Tafel slope of 90 mV/dec. Moreover, a negligible activity degradation was observed for the heterostructure catalyst via continuously catalyzing OER process over 24 h, highlighting the structural robustness of the self-reconstructed Ni-Co-Mo catalyst for practical electrocatalytic applications.