Facile synthesis of amino acids-derived Fe/N-codoped reduced graphene oxide for enhanced ORR electrocatalyst

Here, a simple and green synthesis process of Fe/N-codoped reduced graphene oxide (Fe-N-C/NG) with high electrocatalytic activity for oxygen reduction reaction (ORR) is reported. The synthesis of 3D porous structure of Fe-N-C/NG composites involves thermal drying the mixture of graphene oxide (GO), iron nitrate and aspartic acid (Asp) directly, follow by pyrolysis the mixture. The Asp is introduced as an environment-friendly nitrogen and carbon source, and the iron nitrate serves as the pore-forming agent and a gas producer that prevents the agglomeration of graphene. The as-prepared Fe-N-C/NG exhibits 3D loose porous structure with larger specific surface area (245 m2 g-1). The Fe-NC/NG composite exhibits the onset potential of 0.91 V, a half-wave potential (E1/2 = 0.83 V), low Tafel slope and four-electron selectivity (n = 3.99) in alkaline solution. Furthermore, the stability test manifests the outstanding stability of Fe-NC/NG electrocatalyst and a superior methanol tolerance than Pt/C electrodes. Particularly, when the prepared Fe-NC/NG-3 catalyst is used as an air electrode catalyst in an assembled Zn-air battery, it exhibits a high specific capacity of 848.2 mAh gZn-1 and displays more stability than Pt/C. This work provides an effective strategy for preparing high ORR and Zn-air battery performance Fe/N-codoped reduced graphene oxide materials.