Porous Core–Shell Fe₃C Embedded N-doped Carbon Nanofibers as an Effective Electrocatalysts for Oxygen Reduction Reaction

Abstract

The development of nonprecious-metal-based electrocatalysts with high oxygen reduction reaction (ORR) activity, low cost, and good durability in both alkaline and acidic media is very important for application of full cells. Herein, we developed a facile and economical strategy to obtain porous core-shell Fe3C embedded nitrogen-doped carbon nanofibers (Fe3C@NCNF-X, where X denotes pyrolysis temperature) by electrospinning of polyvinylidene fluoride (PVDF) and FeCl3 mixture, chemical vapor phase polymerization of pyrrole, and followed by pyrolysis of composite nanofibers at high temperatures. Note that the FeCl3 and polypyrrole acts as precursor for Fe3C core and N-doped carbon shell, respectively. Moreover, PVDF not only plays a role as carbon resources, but also provides porous structures due to hydrogen fluoride exposure originated from thermal decomposition of PVDF. The resultant Fe3C@NCNF-X catalysts, particularly Fe3C@NCNF-900, showed efficient electrocatalytic performance for ORR in both alkaline and acidic solutions, which are attributed to the synergistic effect between Fe3C and N-doped carbon as catalytic active sites, and carbon shell protects Fe3C from leaching out. In addition, the Fe3C@NCNF-X catalyst displayed a better long-term stability, free from methanol crossover and CO-poisoning effects than those of Pt/C, which is of great significance for the design and development of advanced electrocatalysts based on nonprecious metals.

A Facile Synthesis of FeCo Nanoparticles Encapsulated in Hierarchical N‐Doped Carbon Nanotube/Nanofiber Hybrids for Overall Water Splitting

“…It is already reported that the excessive pyridinic nitrogen is useful as it coordinates with the metal M (Figure S5 in the SI) and the resulting M−N−C structure improves the local electronic structure leading to faster electrochemical process . The incorporation of N is also evidenced by the C 1s spectrum in the Figure b where a distinct peak at 285.2 eV is observed for C−N bonds . Moreover, C 1s also verifies the presence of C−C/C=C (284.5 eV), C=O (287.3 eV) and π‐π* (290.8 eV) bonds in FeCo@NC‐12 sample.…”

Layered Confinement Reaction: Atomic‐level Dispersed Iron–Nitrogen Co‐Doped Ultrathin Carbon Nanosheets for CO2 Electroreduction

“…To improve the utilization rate of the atoms and expose more active sites, it is considered to improve the catalyst from two aspects. First, the catalytic properties of the material can be improved by regulating the structure of the material, such as ultra‐thinning of the material, regulating the size of the material, and design of multi‐level pore structures to expose more active sites . Xie et al.…”

Binary Nitrogen Precursor-Derived Porous Fe-N-S/C Catalyst for Efficient Oxygen Reduction Reaction in a Zn-Air Battery

“…The high-resolution Fe 2p spectrum of Fe/NS/C-g-C 3 N 4 /TPTZ-1000 presents two major peaks at around 711 and 724 eV, corresponding to Fe 2p 1/2 and Fe 2p 3/2 , respectively (Figure 6f) [15,35]. The dominant peak at 711 eV can be assigned to Fe 3+ or Fe 2+ coordinated with N, which are suggested to be the ORR active centers [15,36]. The peak at 718.5 eV is a satellite peak indicating the co-existence of Fe 3+ and Fe 2+ in the Fe/NS/C-g-C 3 N 4 /TPTZ-1000 [35].…”