Interface Engineering of Ni3N@Fe3N Heterostructure Supported on Carbon Fiber for Enhanced Water Oxidation

Oxygen-evolution reaction (OER), a kinetically sluggish half-reaction involved in water splitting, generally needs large overpotentials to drive the catalytic process, leading to relatively low energy conversion efficiency. Therefore, the development of efficient, low-cost, and stable electrocatalysts based on earth abundant elements is highly desired. Herein, we develop a novel method to construct Ni3N@Fe3N heterostructure anchored on carbon fiber (Ni3N@Fe3N/CF-6) consisting of Fe3N nanoparticles grafted on the metallic Ni3N nanosheets. The results show that of the as-synthesized electrocatalysts, the Ni3N@Fe3N/CF-6 features abundantly exposed interface and active sites, as well as open structure for intimate contact of electrolyte ions and easy release of generated gas. Hence, this Ni3N@Fe3N/CF-6 exhibits a great enhanced OER electrocatalytic performance, including overpotentials as low as 294 mV to achieve a current density of 10 mA cm-2, a small Tafel slope of 40 mV dec-1, and a superior stability at a large current density.