On Active-Site Heterogeneity in Pyrolyzed Carbon-Supported Iron Porphyrin Catalysts for the Electrochemical Reduction of Oxygen:  An In Situ Mössbauer Study

Some FeTPP−Cl/carbon electrocatalysts, heat-treated at temperatures up to 800 °C, have been studied with cyclic voltammetry, x-ray photoelectron spectroscopy, extended X-ray absorption fine structure, and in situ Mössbauer spectroscopy. It appears that the heat treatment induces considerable site he...

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Veröffentlicht in:The journal of physical chemistry. B 2002-12, Vol.106 (50), p.12993-13001
Hauptverfasser: Bouwkamp-Wijnoltz, A. L, Visscher, W, van Veen, J. A. R, Boellaard, E, van der Kraan, A. M, Tang, S. C
Format: Artikel
Sprache:eng
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Zusammenfassung:Some FeTPP−Cl/carbon electrocatalysts, heat-treated at temperatures up to 800 °C, have been studied with cyclic voltammetry, x-ray photoelectron spectroscopy, extended X-ray absorption fine structure, and in situ Mössbauer spectroscopy. It appears that the heat treatment induces considerable site heterogeneity in electronic terms, although structurally the Fe−N4 moiety seems persistent. The data indicate that only part of these Fe−N4 sites contributes to the activity for the electrochemical reduction of O2 but that they operate according to the well-known redox mechanism.
ISSN:1520-6106
1520-5207
DOI:10.1021/jp0266087