The role of trace Fe in Fe–N-doped amorphous carbon with excellent electrocatalytic performance for oxygen reduction reaction

• Fe–N-doped amorphous carbon film catalyst for oxygen reduction was synthesized.
• The catalyst was obtained by dripping iron acetate into N-doped carbon and annealing.
• The optimized catalyst showed excellent activity, stability and methanol tolerance.
• The role of Fe was studied by tuning the Fe content and annealing temperature.
• Trace Fe in film was supposed to form high active FeN4 sites with pyridinic N.

Synthesized by dripping iron acetate into the N-doped carbon film enriched with pyridinic N and followed by annealing at 800 °C, Fe–N-doped amorphous carbon (dFe–N-C) with an Fe content of 0.2 at.% showed excellent electrocatalytic activity, stability and methanol tolerance via a four-electron pathway for oxygen reduction reaction (ORR), which outperformed commercial Pt/C catalyst. More importantly, by tuning the Fe content and annealing temperature, the trace Fe in dFe–N-C was supposed to form high active FeN4 sites with pyridinic N and played an important role in the excellent electrocatalytic performance for ORR.