Elucidating the Structural Composition of an Fe-N-C Catalyst by Nuclear- and Electron-Resonance Techniques.
Stephan WagnerHendrik AuerbachClaudia E TaitIoanna MartinaiouShyam C N KumarChristian KübelIlya SergeevHans-Christian WilleJan BehrendsJuliusz A WolnyVolker SchünemannUlrike I KrammPublished in: Angewandte Chemie (International ed. in English) (2019)
Fe-N-C catalysts are very promising materials for fuel cells and metal-air batteries. This work gives fundamental insights into the structural composition of an Fe-N-C catalyst and highlights the importance of an in-depth characterization. By nuclear- and electron-resonance techniques, we are able to show that even after mild pyrolysis and acid leaching, the catalyst contains considerable fractions of α-iron and, surprisingly, iron oxide. Our work makes it questionable to what extent FeN4 sites can be present in Fe-N-C catalysts prepared by pyrolysis at 900 °C and above. The simulation of the iron partial density of phonon states enables the identification of three FeN4 species in our catalyst, one of them comprising a sixfold coordination with end-on bonded oxygen as one of the axial ligands.
Keyphrases
- metal organic framework
- highly efficient
- visible light
- room temperature
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- ionic liquid
- reduced graphene oxide
- induced apoptosis
- iron oxide
- energy transfer
- municipal solid waste
- carbon dioxide
- heavy metals
- iron deficiency
- gold nanoparticles
- optical coherence tomography
- solar cells
- cell proliferation
- aqueous solution
- oxidative stress
- quantum dots
- pi k akt