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Solid state fluorination on the minute scale: synthesis of WO₃₋ₓFx with photocatalytic activity

Lange, Martin Alexander ; Krysiak, Yaşar ; Hartmann, Jens ; Dewald, Georg ; Cerretti, Giacomo ; Tahir, Muhammad Nawaz ; Panthöfer, Martin ; Barton, Bastian ; Reich, Tobias ; Zeier, Wolfgang G. ; Mondeshki, Mihail ; Kolb, Ute ; Tremel, Wolfgang (2020)
Solid state fluorination on the minute scale: synthesis of WO₃₋ₓFx with photocatalytic activity.
In: Advanced Functional Materials, 30 (13)
doi: 10.1002/adfm.201909051
Artikel, Bibliographie

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Kurzbeschreibung (Abstract)

Solid state reactions are notoriously slow, because the rate‐limiting step is diffusion of atoms or ions through reactant, intermediate, and product crystalline phases. This requires days or even weeks of high temperature treatment, consuming large amounts of energy. Metal oxides are particularly difficult to react, because they have high melting points. The study reports a high‐speed solid state fluorination of WO₃ with Teflon to the oxyfluorides WO₃₋ₓFx on a minute (<10 min) scale by spark plasma sintering, a technique that is used typically for a high‐speed consolidation of powders. Automated electron diffraction analysis reveals an orthorhombic ReO₃‐type structure of WO₃₋ₓFx with F atom disorder as demonstrated by ¹⁹F magic angle spinning nuclear magnetic resonance spectroscopy. The potential of this new approach is demonstrated by the following results. i) Mixed‐ valent tungsten oxide fluorides WO₃₋ₓFx with high F content (0 < x < 0.65) are obtained as metastable products in copious amounts within minutes. ii) The spark plasma sintering technique yields WO₃₋ₓFx nanoparticles with high photocatalytic activity, whereas the corresponding bulk phases obtained by conventional solid‐state (ampoule) reactions have no photocatalytic activity. iii) The catalytic activity is caused by the microstructure originating from the processing by spark plasma sintering.

Typ des Eintrags: Artikel
Erschienen: 2020
Autor(en): Lange, Martin Alexander ; Krysiak, Yaşar ; Hartmann, Jens ; Dewald, Georg ; Cerretti, Giacomo ; Tahir, Muhammad Nawaz ; Panthöfer, Martin ; Barton, Bastian ; Reich, Tobias ; Zeier, Wolfgang G. ; Mondeshki, Mihail ; Kolb, Ute ; Tremel, Wolfgang
Art des Eintrags: Bibliographie
Titel: Solid state fluorination on the minute scale: synthesis of WO₃₋ₓFx with photocatalytic activity
Sprache: Englisch
Publikationsjahr: 2020
Ort: Weinheim
Verlag: Wiley-VCH
Titel der Zeitschrift, Zeitung oder Schriftenreihe: Advanced Functional Materials
Jahrgang/Volume einer Zeitschrift: 30
(Heft-)Nummer: 13
Kollation: 13 Seiten
DOI: 10.1002/adfm.201909051
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Kurzbeschreibung (Abstract):

Solid state reactions are notoriously slow, because the rate‐limiting step is diffusion of atoms or ions through reactant, intermediate, and product crystalline phases. This requires days or even weeks of high temperature treatment, consuming large amounts of energy. Metal oxides are particularly difficult to react, because they have high melting points. The study reports a high‐speed solid state fluorination of WO₃ with Teflon to the oxyfluorides WO₃₋ₓFx on a minute (<10 min) scale by spark plasma sintering, a technique that is used typically for a high‐speed consolidation of powders. Automated electron diffraction analysis reveals an orthorhombic ReO₃‐type structure of WO₃₋ₓFx with F atom disorder as demonstrated by ¹⁹F magic angle spinning nuclear magnetic resonance spectroscopy. The potential of this new approach is demonstrated by the following results. i) Mixed‐ valent tungsten oxide fluorides WO₃₋ₓFx with high F content (0 < x < 0.65) are obtained as metastable products in copious amounts within minutes. ii) The spark plasma sintering technique yields WO₃₋ₓFx nanoparticles with high photocatalytic activity, whereas the corresponding bulk phases obtained by conventional solid‐state (ampoule) reactions have no photocatalytic activity. iii) The catalytic activity is caused by the microstructure originating from the processing by spark plasma sintering.

Freie Schlagworte: automated diffraction tomography, fluorination, photocatalysis, spark plasma synthesis, tungsten oxyfluoride
ID-Nummer: 1909051
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Dedicated with admiration to Prof. Arndt Simon on the occasion of his 80 birthday

Sachgruppe der Dewey Dezimalklassifikatin (DDC): 500 Naturwissenschaften und Mathematik > 540 Chemie
Fachbereich(e)/-gebiet(e): 11 Fachbereich Material- und Geowissenschaften
11 Fachbereich Material- und Geowissenschaften > Geowissenschaften
11 Fachbereich Material- und Geowissenschaften > Geowissenschaften > Fachgebiet Geomaterialwissenschaft
Hinterlegungsdatum: 29 Jan 2024 07:03
Letzte Änderung: 29 Jan 2024 07:04
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