- Titel
- In situ studies on the industrial production process for molybdenum dioxide, MoO2
- Zitierfähige Url:
- https://nbn-resolving.org/urn:nbn:de:bsz:15-qucosa2-1003332
- Quellenangabe
- Zeitschrift für anorganische und allgemeine Chemie
Erscheinungsjahr: 2023
Jahrgang: 649
Heft: 18
ISSN: 0044-2313
E-ISSN: 1521-3749
Artikelnummer: e202300111 - Erstveröffentlichung
- 2023
- Abstract (EN)
- In the industrial production of molybdenum the reduction of molybdenum trioxide with hydrogen is a two-step process. In order to get a deeper understanding of the chemistry involved, in situ studies were performed on the thermal behavior of molybdenum trioxide and the first reduction step to molybdenum dioxide. MoO3 shows a very strong anisotropy for thermal expansion (linear expansion coefficients α in 10−4 K−1: 1.32(4) for a, 5.5(1) for b, −0.246(5) for c). Upon heating in air, preferred orientation in XRPD patterns decreases and the color changes from grey to yellow, probably caused by decreasing oxygen vacancy concentration. The reduction of MoO3 by hydrogen was investigated via in situ X-ray powder diffraction for varying heating rate, hydrogen flow and potassium content. The formation of the intermediate γ-Mo4O11 shows a higher rate for increasing potassium content; it does not play a role whether potassium is present in the starting material MoO3 or in MoO2 formed in the reaction. The high-temperature modification of K2MoO4 was found to crystallize in the α-K2SO4 type (P63/mmc, a=6.3463(2) Å, c= 8.1331(2) Å). Heating up MoO3 in vacuum (1 Pa) with the same T,t protocol as above yields MoO2 even without the presence of hydrogen.
- Andere Ausgabe
- Erstveröffentlichung
DOI: 10.1002/zaac.202300111 - Freie Schlagwörter (EN)
- Molybdenum, solid state chemistry, Rietveld refinement, X-ray powder diffraction, in situ X-ray diffraction, metal oxides, hydrogen, transition metals, smelting
- Klassifikation (DDC)
- 540
- Verlag
- Wiley-VCH, Weinheim
- Förder- / Projektangaben
- Europäischer Fonds für regionale Entwicklung (EFRE)
ID: 100357551 - Deutsche Forschungsgemeinschaft (DFG)
ID: 419433503 - Version / Begutachtungsstatus
- publizierte Version / Verlagsversion
- URN Qucosa
- urn:nbn:de:bsz:15-qucosa2-1003332
- Veröffentlichungsdatum Qucosa
- 13.11.2025
- Dokumenttyp
- Artikel
- Sprache des Dokumentes
- Englisch
- Lizenz / Rechtehinweis
CC BY-NC-ND 4.0