Biomimicry-inspired fish scale-like Ni3N/FeNi3N/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 Ni3N/FeNi3N/NF nanoarrays with a fish scale-like structure, which endowed the Ni3N/FeNi3N/NF nanoarrays with rapid infiltration of aqueous solution within 60 ms and 169 degrees bubble contact angle, is demonstrated. The optimal Ni3N/FeNi3N/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 Ni3N/FeNi3N/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 Ni3N/FeNi3N/NF electrocatalysts.

Automated summary

In this study, a biomimicry-inspired design of Ni3N/FeNi3N/NF nanoarrays with a fish scale-like structure was demonstrated, which allowed for rapid infiltration of aqueous solution within 60 ms and a 169 degrees bubble contact angle. The optimized Ni3N/FeNi3N/NF sample exhibited catalytic activity with low overpotentials for both the hydrogen evolution reaction (HER) and the anodic-coupled urea oxidation reaction (UOR). Furthermore, the rapid bubble extraction within the nanoarrays ensured excellent cycling stability for HER over 100 hours at a current density of 50 mA cm(-2). The scale-up experiment indicated the potential for industrialized application of the prepared electrocatalysts.