Biomimicry-inspired fish scale-like Ni 3 N/FeNi 3 N/NF superhydrophilic/superaerophobic nanoarrays displaying high electrocatalytic performance.

The mass transfer efficiency and structural stability of the electrode are critical for industrialized water electrolysis operations. Herein, the biomimicry-inspired design of Ni 3 N/FeNi 3 N/NF nanoarrays with a fish scale-like structure, which endowed the Ni 3 N/FeNi 3 N/NF nanoarrays with rapid infiltration of aqueous solution within 60 ms and 169° bubble contact angle, is demonstrated. The optimal Ni 3 N/FeNi 3 N/NF sample displayed catalytic activity with hydrogen evolution reaction (HER) overpotentials of only 48 mV at 10 mA cm -2 and 102 mV at 100 mA cm -2 . Similarly, the overpotential of the anodic-coupled urea oxidation reaction (UOR) was only 1.3 V at 10 mA cm -2 and 1.35 V at 100 mA cm -2 . Besides, the small impact resulting from the rapid bubble extraction within the Ni 3 N/FeNi 3 N/NF nanoarrays ensured excellent HER cycling stability over 100 h at a current density of 50 mA cm -2 . The further scale-up experiment suggests the industrialization prospects of the prepared Ni 3 N/FeNi 3 N/NF electrocatalysts.