Porous carbon polyhedrons with exclusive Metal-NX moieties for efficient oxygen reduction reaction

摘要

This work has manufactured a series of M-N-X/C (M = Fe, Cu, Ni) ORR catalysts by the pyrolysis of metal tetraphenylporphyrin (MTPP) adsorbed onto N-doped porous carbon polyhedrons (NPCP) derived from ZIF-8. The comprehensive characterization data shows that the prepared M-N-X/C catalysts have hierarchical porous structure with high specific surface area and abundant M-N-X moieties. All prepared M-N-X/C catalysts exhibit good ORR performance. The ORR half-wave potentials E-1/2 of Fe-N-X/C, Cu-N-X/C and Ni-N-X/C catalyst are 0.885, 0.801 and 0.755 V respectively. The rotating ring-disk electrode (RRDE) test reveals that the ORR of Fe-N-X/C is a four electron process. While a two and four electron mixing ORR process are observed for Cu-N-X/C and Ni-N-X/C. In an alkaline medium, E-1/2 of Fe-N-X/C is observed 44 mV higher than that of commercial Pt/C. Also, Fe-N-X/C catalyst has outstanding long-term durability and good methanol resistance.

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