Hierarchical Porous Carbon Doped with Iron/Nitrogen/Sulfur for Efficient Oxygen Reduction Reaction
Hierarchical porous Fe/N/S-doped carbon with a high content of graphitic nitrogen (FeNS/HPC) has been successfully synthesized by a facile dual-template method. FeNS/HPC shows not only macropores resulting from the dissolution of the SiO2 template, but abundant mesopores were also obtained after rem...
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Veröffentlicht in: | ACS applied materials & interfaces 2017-06, Vol.9 (24), p.20963-20973 |
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Hauptverfasser: | , , , , , , , , |
Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | Hierarchical porous Fe/N/S-doped carbon with a high content of graphitic nitrogen (FeNS/HPC) has been successfully synthesized by a facile dual-template method. FeNS/HPC shows not only macropores resulting from the dissolution of the SiO2 template, but abundant mesopores were also obtained after removing the in situ generated Fe2O3 nanoparticles on the ultrathin (∼4 nm) carbon shell of the macropores. Moreover, micropores are produced during the thermal pyrolysis of the carbon precursors. With respect to the electrochemical performance in the oxygen reduction reaction (ORR), FeNS/HPC not only exceeds other prepared porous carbon materials completely but also shows higher onset potential (0.97 vs 0.93 V), half-wave potentials (0.87 vs 0.83 V), and diffusion current density (5.5 vs 5.3 mA cm–2) than those of Pt/C. Furthermore, FeNS/HPC also exhibits outstanding stability and methanol tolerance, making it a competent candidate for ORR. The following aspects contribute to its excellent ORR performance. (1) High content of graphitic N (5.1%) and codoping of pyridinic N species, thiophene-S, FeN x , and graphitic carbon-encapsulated iron nanoparticles, providing highly active sites. (2) The hierarchical porous mesh structure with micro-, meso-, and macroporosity, accelerating the mass transfer and facilitating full utilization of the active sites. (3) The high specific surface area (1148 m2 g–1) of the graphitic carbon shell, assuring a large interface and rapid electron conduction for ORR. |
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ISSN: | 1944-8244 1944-8252 |
DOI: | 10.1021/acsami.7b02306 |