Fabrication of Fe Nanoparticles into N-doped Mesoporous Carbon Nanotube Derived from Rice-Like Fe/N-MOF and Its ORR Catalytic Performance for MFC

The development of non-noble metal oxidation reduction catalysts(ORR) to improve microbial fuel cell(MFC) performance remains extremely challenging. Herein, the nitrogen-doped iron-based porous carbon nanotube Fe/N@MC-T ORR catalysts were derived from Fe/N-MOF by pyrolyzation using acetonitrile as the nitrogen precursor in a low-cost organic solvent. The Fe/N@MC-T catalysts under different pyrolysis temperatures were characterized by SEM, TEM, BET, XRD, and XPS techniques. Fe/N-MOF showed a smooth rice-like structure with a particle size of about 400×50 nm~2. The Fe species in Fe/N@MC-T mainly exists in the form of zero-valent iron with a small amount of FeC. The results of electrochemical tests revealed that the onset and half-wave potentials of Fe/N@MC-700 were 0.89 V and 0.80 V, respectively, which were only slightly lower than those of the commercial Pt/C(0.92 V and 0.82 V). The MFC with Fe/N@MC-700 showed a highest power density of 864.1 mW/m~2, which was about 2.25 times that of MFC with carbon cloth, and was slightly lower than that of MFC with Pt/C(20%)(1002.0 mW/m~2), which demonstrated that the Fe particles wrapped in carbon nanotubes possessed a relatively high ORR activity.