Highly efficient catalysts for oxygen reduction using well-dispersed iron carbide nanoparticles embedded in multichannel hollow nanofibers

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2020-09, Vol.8 (35), p.18125-18131
• Main Authors: Xia, Hongyin, Zhang, Shan, Zhu, Xiaoqing, Xing, Huanhuan, Xue, Yuan, Huang, Bolong, Sun, Mingzi, Li, Jing, Wang, Erkang
• Format: Article
• Language: English
• Subjects: Catalysts; Cementite; Chemical reduction; Chemical synthesis; Density functional theory; Durability; Electrocatalysts; Electron transfer; Electrons; Iron; Iron carbides; Mass transport; Nanofibers; Nanoparticles; Oxygen; Oxygen reduction reactions; Platinum
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d0ta06306a

Engineering catalytic materials into appropriate structures to get the structural benefits is vital for harvesting unprecedented catalytic efficiency in the oxygen reduction reaction (ORR). Herein, well-dispersed and highly active iron carbide nanoparticles (Fe 3 C NPs) were encapsulated in multichannel hollow nanofibers (MHNFs) to construct Fe 3 C@MHNF catalysts, which were synthesized via simple electrospinning and calcination steps. The well-defined inner channels with high conductivity and a porous structure enable the rapid electron transfer and mass transport for the ORR. And the resulting hybrid electrocatalyst with Fe 3 C NPs serving as active sites exhibits highly efficient activity with a half-wave potential of 0.90 V vs. the reversible hydrogen electrode (RHE), which surpasses that of the commercial platinum on carbon (Pt/C) catalyst (a half-wave potential of 0.84 V vs. RHE). The catalyst shows robust durability with negligible activity decay after 10 000 cycles. Density functional theory calculations confirm that the introduction of MHNFs significantly improves the electron transfer and exchange capability. The formed interfacial region not only induces linear correlation in both electronic structures and binding energies but also alleviates the barrier of site-to-site electron transfer between Fe 3 C NPs and MHNFs for the ORR process. Well-dispersed and highly active iron carbide nanoparticles encapsulated in multichannel hollow nanofibers (Fe 3 C@MHNFs) were synthesized via simple electrospinning and calcination steps, exhibiting highly efficient activity and robust durability for oxygen reduction.