In Situ Synthesis and Electrocatalytic Performance of Fe/Fe2.5C/Fe3N/Nitrogen‐Doped Carbon Nanotubes for the Oxygen Reduction Reaction

Abstract I n this study, a novel one‐dimensional iron‐based nitrogen‐doped carbon nanotube (N‐CNT) nanocomposite (Fe/Fe 2.5 C/Fe 3 N/N‐CNT) was successfully synthesized in situ by using a facile and low‐cost method. In alkaline media, the typical product (Fe/Fe 2.5 C/Fe 3 N/N‐CNT‐30) showed an good onset potential ( E onset =0.93 V vs RHE), half‐wave potential ( E 1/2 =0.79 V vs RHE), and current density ( J =6.62 mA cm −2 at 0.2 V vs RHE), especially compared to the commercial 20 % Pt/C catalyst (0.95 V, 0.82 V, 5.61 mA cm −2 , respectively). In acidic medium, it also exhibits a good oxygen reduction reaction (ORR) activity. Moreover, Fe/Fe 2.5 C/Fe 3 N/N‐CNT‐30 exhibited superior long‐term durability and methanol tolerance compared to Pt/C in both alkaline and acidic media. The excellent electrocatalytic performance of this material is attributed to the abundant carbon defects in the carbon structure, the high content doping of pyridinic N and graphitic N into the CNTs, the multi‐model Fe species as active sites, and the fact that most Fe species within the CNTs avoid corrosion from electrolyte. This study paves a new way for highly active ORR electrocatalysts and promotes the rapid development of CNTs in some frontier fields.