Journal of thermal analysis

, Volume 37, Issue 4, pp 849–860 | Cite as

Thermal decomposition of ammonium metavanadate doped with Fe, Co or Ni hydroxides

  • A. A. Said


The thermal decomposition of pure ammonium metavanadate (AMV) and of AMV doped with Fe3+,Co2+ or Ni2+ ions was investigated by TG, DTA, IR and X-ray diffraction. The results obtained revealed that the presence of these dopants enhances the formation of the intermediate compounds V2O5 solid. Some of the V5+ ions of the V2O5 lattice seemed to be reduced to V4+ ions. The activation energies of the different decomposition stages for all samples were calculated. The doped solids calcined at 450°C were characterized by the determination ofSbet and by electrical conductivity measurements. The mechanisms by which these ions affect the properties of the solids produced are discussed in relation to the defect structure created by the doping process.


Activation Energy Thermal Decomposition V2O5 Intermediate Compound Decomposition Stage 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Mittels TG, DTA, IR und Röntgendiffraktion wurde die thermische Zersetzung von reinem Ammoniummetavanadat (AMV) und von AMV, versetzt mit Fe3+, Co2+ oder Ni2+, untersucht. Die Ergebnisse zeigen, daß die Bildung von Zwischenprodukten und festem V2O5 durch die Gegenwart der Zusätze begünstigt wird. Einige der V5+-Ionen des V2O5 Gitters scheinen zu V4+-Ionen reduziert zu sein. Für alle Proben wurde die Aktivierungsenergie der verschiedenen Zersetzungsschritte berechnet. Die versetzten Feststoffe, die bei 450°C kalziniert wurden, konnten durch die Bestimmung vonSbet und durch elektrische Leitfähigkeitsmessungen charakterisiert werden. Der Mechanismus, über welchen diese Ionen die Eigenschaften der Feststoffe beeinflussen, wurde hinsichtlich der hervorgerufenen Defektstruktur diskutiert.


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Copyright information

© Wiley Heyden Ltd., Chichester and Akadémiai Kiadó, Budapest 1991

Authors and Affiliations

  • A. A. Said
    • 1
  1. 1.Department of Chemistry, Faculty of ScienceUnited Arab Emirates UniversityAl-AinU. A. E.

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