Electrospun Fe₂C-loaded carbon nanofibers as efficient electrocatalysts for oxygen reduction reaction

Carbon-based non-precious metal catalysts have been regarded as the most promising alternatives to the state-of-art Pt/C catalyst for the oxygen reduction reaction (ORR). However, there are still some unresolved challenges such as agglomeration of nanoparticles, complex preparation process and low production efficiency, which severely hamper the large-scale production of non-precious metal catalysts. Herein, a novel carbon-based non-precious metal catalyst, i.e. iron carbide nanoparticles embedded on carbon nanofibers (Fe₂C/CNFs), prepared via the direct pyrolysis of carbon- and iron-containing Janus fibrous precursors obtained by electrospinning. The Fe₂C/CNF catalyst shows uniform dispersion and narrow size distribution of Fe₂C nanoparticles embedded on the CNFs. The obtained catalyst exhibits positive onset potential (0.87 V versus RHE), large kinetic current density (1.9 mA cm^-2), and nearly follows the effective four-electron route, suggesting an outstanding electrocatalytic activity for the ORR in 0.1 M of KOH solution. Besides, its stability is better than that of the commercial Pt/C catalyst, due to the strong binding force between Fe₂C particles and CNFs. This strategy opens new avenues for the design and efficient production of promising electrocatalysts for the ORR.