A high-performance nitrogen-rich ZIF-8-derived Fe-NC electrocatalyst for the oxygen reduction reaction

Metal–air batteries have shown tremendous potential as devices for electrical energy storage and conversion; however, their commercial applications are limited owing to the high costs of precious metal catalysts. In this study, urea was employed as a dispersant and as an additional nitrogen source to synthesize zeolitic imidazolate framework-derived iron-nitrogen-carbon catalysts (ZIF-8-derived Fe-NCs). The fabricated nitrogen-rich catalyst was found to have a high specific surface area and numerous surface defects, while maintaining the original ZIF-8 morphology. Electrochemical analysis with a rotating ring-disk electrode revealed that the onset potential of nitrogen-rich Fe-NC was 0.91 V at 1600 rpm with a limiting current density of 5.38 mA·cm−2, which indicated a high catalytic activity for the oxygen reduction reaction. Additionally, the decent stability of the catalyst was confirmed by a 2 h cycle test.