Ancient Chemistry “Pharaoh’s Snakes” for Efficient Fe-/N-Doped Carbon Electrocatalysts

The method of fabricating nonprecious metal electrocatalysts with high activity and durability through a facile and eco-friendly procedure is of great significance to the development of low-cost fuel cells and metal–air batteries. Herein, we present that an ancient chemical reaction of “Pharaoh’s snakes” can be a fast and convenient technique to prepare Fe-/N-doped carbon (Fe/N–C) nanosheet/nanotube electrocatalysts with sugar, soda, melamine, and iron nitrate as precursors. The resultant Fe/N–C catalyst has a hierarchically porous structure, a large surface area, and uniformly distributed active sites. The catalyst shows high electrocatalytic activities toward both the oxygen reduction reaction with a half-wave potential of 0.90 V (vs reversible hydrogen electrode) better than that of Pt/C and the oxygen evolution reaction with an overpotential of 0.46 V at the current density of 10 mA cm–2 comparable to that of RuO2. The activity and stability of the catalyst are also evaluated in primary and rechargeable Zn–air batteries. In both conditions, three-dimensional Fe/N–C exhibited performances superior to Pt/C. Our work demonstrates a success of utilizing an ancient science to make a state-of-the-art electrocatalyst.