Phase evolution of vanadium oxides obtained through temperature programmed calcinations of ammonium vanadate in hydrogen atmosphere and their humidity sensing properties
| dc.contributor.author | Akande, A.A. | |
| dc.contributor.author | Linganiso, E.C. | |
| dc.contributor.author | Dhonge, B.P. | |
| dc.contributor.author | Rammutla, K.E. | |
| dc.contributor.author | Machatine, Augusto Gonçalo Jose | |
| dc.contributor.author | Prinsloo, Linda Charlotta | |
| dc.contributor.author | Kunert, Herbert W. | |
| dc.contributor.author | Mwakikunga, B.W. | |
| dc.date.accessioned | 2015-03-05T09:02:45Z | |
| dc.date.available | 2015-03-05T09:02:45Z | |
| dc.date.issued | 2015-02 | |
| dc.description.abstract | The possibility of obtaining vanadium dioxide (VO2) [wherein the vanadium ionic state is 4þ] from a precursor of ammonium metavanadate (NH4VO3) bearing the ion V5þ is investigated. The reduction is carried out by calcining the NH4VO3 powders in similar concentrations of H2 flow at varying temperatures. The resulting powders have been studied by several techniques including XRD, Raman spectroscopy, FTIR, TEM, BET and DSC. It is found that remnants of bright yellow V5þ still exist up to calcination temperatures of 100 C after which the sky-blue VO2 dominates at calcination temperatures of 150 C e250 C. There is a population surge of metastable dark-blue V6O13 (where V is in between V4þ and V5þ ionic states) between 250 C and 300 C. However above 350 C the material reverts to the stable V5þ in the yellow-orange V2O5. XPS/EDS and VSM confirm the order of appearance to be VO2(150 C) / V6O13(200 C) / V2O5 (350 C). | en_ZA |
| dc.description.librarian | hb2015 | en_ZA |
| dc.description.sponsorship | India-Brazil-South Africa trilateral cooperation under the National Research Foundation (NRF) grant number HGER24X. | en_ZA |
| dc.description.uri | http://www.elsevier.com/locate/matchemphys | en_ZA |
| dc.identifier.citation | Akande, AA, Linganiso, EC, Dhonge, BP, Rammutla, KE, Machatine, AGJ, Prinsloo, LC, Kunert, HW & Mwakikunga, BW 2014, 'Phase evolution of vanadium oxides obtained through temperature programmed calcinations of ammonium vanadate in hydrogen atmosphere and their humidity sensing properties', Materials Chemistry and Physics, vol. 151, no. 206-2015. | en_ZA |
| dc.identifier.issn | 0254-0584 | |
| dc.identifier.other | 10.1016/j.matchemphys.2014.11.055 | |
| dc.identifier.uri | http://hdl.handle.net/2263/43873 | |
| dc.language.iso | en | en_ZA |
| dc.publisher | Elsevier | en_ZA |
| dc.rights | © 2014 Elsevier B.V. All rights reserved. Notice : this is the author’s version of a work that was accepted for publication in Materials Chemistry and Physics. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Materials Chemistry and Physics, vol. 151, pp. 206-215, 2015. doi : 10.1016/j.matchemphys.2014.11.055. | en_ZA |
| dc.subject | Annealing | en_ZA |
| dc.subject | Oxidation | en_ZA |
| dc.subject | Phase transition | en_ZA |
| dc.subject | Thermogravimetric analysis | en_ZA |
| dc.subject | X-ray diffraction (XRD) | en_ZA |
| dc.subject | Topology | en_ZA |
| dc.subject | Adsorption | en_ZA |
| dc.subject | Desorption | en_ZA |
| dc.subject | Differential scanning calorimetry (DSC) | en_ZA |
| dc.subject | X-ray photo-electron spectroscopy (XPS) | en_ZA |
| dc.subject | Vibrating sample magnetometer (VSM) | en_ZA |
| dc.title | Phase evolution of vanadium oxides obtained through temperature programmed calcinations of ammonium vanadate in hydrogen atmosphere and their humidity sensing properties | en_ZA |
| dc.type | Postprint Article | en_ZA |