Ammonia gas sensing characteristics of V2O5 nanostructures: A combined experimental and ab initio density functional theory approach.
In: Journal of Alloys & Compounds, Jg. 821 (2020-04-25), S. N.PAG
Online
academicJournal
Zugriff:
A combined experimental and density functional theory of α-V 2 O 5 for ammonia gas sensing have been investigated. The material was synthesized from hydrated NH 4 VO 3 in CVD at 400 °C in N 2 atmosphere for different time (12 h and 24 h). Highly crystalline orthorhombic α-V 2 O 5 nano-rods with dominant (001) and (110) planes/facets nano-rods were observed from XRD, SEM and TEM characterizations. Using VSM technique, para-to ferro-magnetic transition was observed in the α-V 2 O 5 nanoparticles synthesized at 24 h. Improved gas sensing was observed in case of the paramagnetic α-V 2 O 5 nano-rods (nanoparticles synthesized at 12 h) compared with the one synthesized at 24 h. Additionally, significant rise in gas sensing response was observed around the metal to insulator transition temperature. Calculation of adsorption of NH 3 molecule(s) on (001), (110), (200) and (400) facets showed that (001), (200) and (400) possessed more active sites than (110) surface. However, at higher concentration of NH 3 molecules, the number of adsorbed molecules was found to be limited by the available adsorption sites in the case of (001) thereby causing the surface to be unstable. DFT calculations were also used to investigate NH 3 adsorption on (110) surface of α-V 2 O 5 with the analysis showing exponential decrease in the electronic band gap of the material's surface with the increasing numbers of NH 3 loadings. • Para-to ferro-magnetic transition behaviour of the Orthorhombic α-V 2 O 5 nano-rods particles. • Excellent NH 3 gas response property in the vicinity of α-V 2 O 5 's metal-to- insulator transition temperature. • Observation of inverse relationship of magnetic and NH 3 sensing property of α-V 2 O 5 nano-rods particles. • Correlation of DFT adsorption energy's profile and the actual experimental sensing response of α-V 2 O 5. • Reduction in the surface electronic band gap with increasing number of adsorbed NH 3 molecules. [ABSTRACT FROM AUTHOR]
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Ammonia gas sensing characteristics of V2O5 nanostructures: A combined experimental and ab initio density functional theory approach.
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Autor/in / Beteiligte Person: | Akande, A.A. ; Mosuang, T. ; Ouma, C.N.M. ; Benecha, E.M. ; Tesfamicheal, T. ; Roro, K. ; Machatine, A.G.J. ; Mwakikunga, B.W. |
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Zeitschrift: | Journal of Alloys & Compounds, Jg. 821 (2020-04-25), S. N.PAG |
Veröffentlichung: | 2020 |
Medientyp: | academicJournal |
ISSN: | 0925-8388 (print) |
DOI: | 10.1016/j.jallcom.2019.153565 |
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