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Journal of thermal analysis

, Volume 37, Issue 5, pp 959–967 | Cite as

The role of copper-chromium oxide catalysts in the thermal decomposition of ammonium perchlorate

  • A. A. Said
Article

Abstract

The catalytic effects of doped or mixed CuO-Cr2O3 oxides on the thermal decomposition of ammonium perchlorate (AP) were investigated by using DTA, electrical conductivity and X-ray diffraction techniques. The results obtained revealed that the decrease in the defect electron of CuO catalyst doped with 1 at.% Cr3+ inhibited its activity, while the opposite effect was observed when Cr2O3 was doped with 1 at.% Cu2+. On increase of the concentrations of both oxides, the catalyst containing 70 at.% Cr3+ was found to be the most active during the decomposition of AP. The existence of CuCr2O4 at this ratio was demonstrated by X-ray diffraction. The activity of this spinel was explained on the basis of a hopping mechanism between Cr3+/Cr4+ active sites. Finally, the activation energies of different decomposition stages of AP alone and mixed with catalysts were calculated.

Keywords

Activation Energy Electrical Conductivity Thermal Decomposition Perchlorate Oxide Catalyst 
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.

Zusammenfassung

Mittels DTA, Röntgendiffraktion und elektrischer LeitfÄhigkeit wurden die katalytischen Wirkungen von versetzten oder gemischten CuO-Cr2O3 Oxiden auf die thermische Zersetzung von Ammoniumperchlorat (AP) untersucht. Die erhaltenen Ergebnisse zeigen, da\ die Abnahme an Defektelektronen von CuO-Katalysator, versetzt mit 1 mol% Cr3+, seine AktivitÄt vermindern, wÄhrend ein entgegengesetzter Effekt bei Cr2O3 beobachtet wird, das mit 1 mol% Cu2+ versetzt ist.

Durch Erhöhung der Konzentrationen beider Oxide zeigt der Katalysator bei der Zersetzung von AP die grö\te AktivitÄt bei einem Cr3+-Gehalt von 70 mol%. Mittels Röntgendiffraktion konnte bei dieser Zusammensetzung die Existenz von CuCr2O4 gezeigt werden. Die AktivitÄt dieser Spinellstruktur wurde durch einen Hüpfmechanismus zwischen Cr3+/Cr4+-aktiven Stellen erklÄrt. Weiterhin wurden die Aktivierungsenergien von verschiedenen Zersetzungsstufen von AP mit und ohne Katalysatoren berechnet.

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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-AinUAE

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