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In Situ and Ex Situ X‑ray Diffraction and Small-Angle X‑ray Scattering Investigations of the Sol−Gel Synthesis of Fe3N and Fe3C
- Iron nitride (Fe3N) and iron carbide (Fe3C) nanoparticles can be prepared via sol−gel synthesis. While sol−gel methods are simple, it can be difficult to control the crystalline composition, i.e., to achieve a Rietveld-pure product. In a previous in situ synchrotron study of the sol−gel synthesis of Fe3N/Fe3C, we showed that the reaction proceeds as follows: Fe3O4 → FeOx → Fe3N → Fe3C. There was considerable overlap between the different phases, but we were unable to ascertain whether this was due to the experimental setup (side-on heating of a quartz capillary which could lead to thermal gradients) or whether individual particle reactions proceed at different rates. In this paper, we use in situ wide- and small-angle X-ray scattering (wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering (SAXS)) to demonstrate that the overlapping phases are indeed due to variable reaction rates. While the initial oxide nanoparticles have a small range of diameters, the size rangeIron nitride (Fe3N) and iron carbide (Fe3C) nanoparticles can be prepared via sol−gel synthesis. While sol−gel methods are simple, it can be difficult to control the crystalline composition, i.e., to achieve a Rietveld-pure product. In a previous in situ synchrotron study of the sol−gel synthesis of Fe3N/Fe3C, we showed that the reaction proceeds as follows: Fe3O4 → FeOx → Fe3N → Fe3C. There was considerable overlap between the different phases, but we were unable to ascertain whether this was due to the experimental setup (side-on heating of a quartz capillary which could lead to thermal gradients) or whether individual particle reactions proceed at different rates. In this paper, we use in situ wide- and small-angle X-ray scattering (wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering (SAXS)) to demonstrate that the overlapping phases are indeed due to variable reaction rates. While the initial oxide nanoparticles have a small range of diameters, the size range expands considerably and very rapidly during the oxide−nitride transition. This has implications for the isolation of Rietveld-pure Fe3N, and in an extensive laboratory study, we were indeed unable to isolate phasepure Fe3N. However, we made the surprising discovery that Rietveld-pure Fe3C nanoparticles can be produced at 500 °C with a sufficient furnace dwell time. This is considerably lower than the previous reports of the sol−gel synthesis of Fe3C nanoparticles.…
Autor*innen: | M. S. Chambers, R. D. Hunter, M. J. Hollamby, Brian Richard PauwORCiD, A. J. Smith, T. Snow, A. E. Danks, Z. Schnepp |
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Dokumenttyp: | Zeitschriftenartikel |
Veröffentlichungsform: | Verlagsliteratur |
Sprache: | Englisch |
Titel des übergeordneten Werkes (Englisch): | Inorganic Chemistry |
Jahr der Erstveröffentlichung: | 2022 |
Organisationseinheit der BAM: | 6 Materialchemie |
6 Materialchemie / 6.5 Synthese und Streuverfahren nanostrukturierter Materialien | |
Veröffentlichende Institution: | Bundesanstalt für Materialforschung und -prüfung (BAM) |
Verlag: | ACS Publications |
Verlagsort: | Washington |
Jahrgang/Band: | 61 |
Ausgabe/Heft: | 18 |
Erste Seite: | 6742 |
Letzte Seite: | 6749 |
DDC-Klassifikation: | Naturwissenschaften und Mathematik / Chemie / Analytische Chemie |
Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Ingenieurwissenschaften und zugeordnete Tätigkeiten | |
Freie Schlagwörter: | Catalyst; Diffraction; Ex-situ; In-situ; Iron carbide; Iron nitride; Nanoparticles; SAXS; Scattering; Small-angle X-ray Scattering; Sol-gel; Synchrotron; Synthesis; XRD |
Themenfelder/Aktivitätsfelder der BAM: | Chemie und Prozesstechnik |
Material | |
Material / Nano | |
DOI: | 10.1021/acs.inorgchem.1c03442 |
URN: | urn:nbn:de:kobv:b43-548226 |
Verfügbarkeit des Dokuments: | Datei für die Öffentlichkeit verfügbar ("Open Access") |
Lizenz (Deutsch): | Creative Commons - CC BY - Namensnennung 4.0 International |
Datum der Freischaltung: | 16.05.2022 |
Referierte Publikation: | Ja |
Datum der Eintragung als referierte Publikation: | 16.05.2022 |
Schriftenreihen ohne Nummerierung: | Wissenschaftliche Artikel der BAM |