Fe, N-doped carbon spheres prepared by electrospinning method as high efficiency oxygen reduction catalyst

Abstract

Electrocatalysts for the oxygen reduction reaction (ORR) are crucial in metal–air batteries, fuel cells and other electrochemical devices. In this study, iron and nitrogen co-doped carbon sphere electrocatalysts were synthesized by electrospinning and thermal treatment. According to the results, the catalyst marked as Fe–N/MCS-181 (Fe, N-doped mesoporous carbon spheres, iron nitrate nonahydrate as the iron source) has not only the highest iron content, which reaches up to 0.13%, but also a spherical shape. And its pore sizes are 11 and 35 nm. For the electrochemical performance, the onset potential (E_onset) of Fe–N/MCS-181 is −0.018 V, while the half-wave potential (E_1/2) of Fe–N/MCS-181 is −0.145 V, which is better than the commercial Pt/C catalyst (E_1/2 is −0.18 V). The durability of the Fe–N/MCS-181 catalyst is better than commercial Pt/C. After 10 000 s, the retention ratio of current density is 86.4%, while that of the commercial Pt/C catalyst is 84.2%. At the same time, the methanol tolerance of the Fe–N/MCS-181 catalyst is also excellent. After adding methanol, the current density of the Fe–N/MCS-181 catalyst has no obvious change. This study provides an easy method to fabricate a highly efficient and durable Fe, N-doped carbon catalyst for the oxygen reduction reaction.