7-11 July 2014
Africa/Johannesburg timezone
<a href="http://events.saip.org.za/internalPage.py?pageId=16&confId=34"><font color=#0000ff>SAIP2014 Proceedings published on 17 April 2015</font></a>

Phase evolution of vanadium oxides obtained through temperature programmed annealing of ammonium vanadate in hydrogen atmosphere

8 Jul 2014, 14:20
D Les 202

D Les 202

Oral Presentation Track A - Division for Physics of Condensed Matter and Materials DPCMM2


Mr Amos Akande (University of Limpopo)

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Abstract content <br> &nbsp; (Max 300 words)<br><a href="http://events.saip.org.za/getFile.py/access?resId=0&materialId=0&confId=34" target="_blank">Formatting &<br>Special chars</a>

The possibility of obtaining vanadium dioxide (VO2) [wherein the vanadium ionic state is 4+] from a precursor of ammonium metavanadate (NH4VO3) bearing the ion V5+ is investigated.
The reduction is carried out by annealing the NH4VO3 powders in similar concentrations of H2 flow at varying temperatures. The resulting powders have been studied by several techniques including X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), Transmission electron microscope (TEM), Brunauer-Emmiter-Teller (BET) and Differential scanning calorimetry (DSC). It is found that remnants of bright yellow V5+ still exist up to annealing temperatures of 100 0C after which the sky-blue VO2 dominates at annealing temperatures of 150 0C to 250 0C. There is a population surge of metastable dark-blue V6O13 (where V is in between V4+ and V5+ ionic states) between 250 0C and 300 0C. However above 350 0C the material reverts to the stable V5+ in the yellow-orange V2O5.

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Main supervisor (name and email)<br>and his / her institution

Dr. Erasmus K Rammutla, erasmus.rammutla@ul.ac.za University of Limpopo, Dept. of Physics, P/Bag X1106, Sovenga, 0727.

Primary author

Mr Amos Akande (University of Limpopo)


Dr Bonex Mwakikunga (CSIR) Dr Erasmus Koena Rammutla (University of Limpopo)

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