Iron and Nitrogen-Doped Porous Carbon Catalysts Derived from MOF-5 with Three-Dimensional Structures Achieve High Oxygen Reduction Reactivity

Iron and nitrogen-doped carbon (Fe–N/C) catalysts have been demonstrated to be effective in facilitating oxygen reduction reactions, making them a promising substitute for noble metal catalysts. Various factors, including the availability of transport channels and active sites, influence the performance of Fe–N/C. A Fe, N-doped porous carbon (Fe/NPC) catalyst with a three-dimensional structure was synthesized by modifying the precursor’s morphology, composed of one-dimensional bamboo-like carbon nanotubes interwoven with two-dimensional graphitic carbon nanosheets. The high surface area of the nanosheets furnishes abundant active sites, while the nanotubes suppress sheet restacking and facilitate rapid charge/mass transport. Moreover, the synergistic interplay between Fe3C and Fe–Nx sites imparts oxygen-reduction activity on par with Pt/C, underscoring its promise as a viable alternative. The Fe/NPC loading of 0.1 mg cm–2 showed a half-wave potential of 0.858 V. The current decay was only 7.6% after a 40,000 s constant voltage test. Upon integration of the catalyst into a zinc–air battery, the resulting cell demonstrated a noteworthy peak power density of 166.2 mW cm–2 and an impressive energy density of 952.7 Wh kg–1 Zn.