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 |
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Hauptverfasser: | , , , , , |
Format: | Artikel |
Sprache: | eng |
Online-Zugang: | Volltext |
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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. |
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ISSN: | 1520-6106 1520-5207 |
DOI: | 10.1021/jp0266087 |