Chimowa, GeorgeTshabalala, Zamaswazi PAkande, Amos ABepete, GMwakikunga, Bonex WRay, Suprakas SBenechada, EM2018-04-062018-04-062017-08Chimowa, G., Tshabalala, Z.P., Akande, A.A., Bepete, G., Mwakikunga, B.W., Ray, S.S. and Benechada, E.M. 2017. Improving methane gas sensing properties of multi-walled carbonnanotubes by vanadium oxide filling. Sensor and Actuators B: Chemical, vol 247, pp 11-180925-4005https://www.sciencedirect.com/science/article/pii/S0925400517303945http://hdl.handle.net/10204/10167Copyright: 2017 Elsevier. Due to copyright restrictions, the attached PDF file only contains the abstract of the full text item. For access to the full text item, please consult the publisher's website. The definitive version of the work is published in Sensor and Actuators B: Chemical, vol 247, pp 11-18Manipulation of electrical properties and hence gas sensing properties of multi-walled carbon nanotubes (MWNTs) by filling the inner wall with vanadium oxide is presented. Using a simple capillary technique, MWNTs are filled with vanadium metal which is later oxidized. It is observed that the methane gas detection response time at room temperature (293 K), is significantly improved from 138 s (in vanadium pentoxide) to 16 s (in filled MWNTs) while the recovery times changes from 234 s to 120 s respectively. The response sensitivity of the unfilled CNTs is improved from 0.5% to 1.5% due to the metal oxide filling. Using theoretical Density Functional Theory (DFT) electronic structure calculations, we show that the enhanced response is due to the increased density of states around the Fermi level of the composite material as a result of the encapsulated metal oxide. And we propose an adsorption mechanism at three different sites of the MWNTs surface based on the Langmuir model. This work also highlights the influence of ambient oxygen in carbon nanotube based sensors, an aspect that has not been clearly addressed in many previous theoretical and experimental studies.enCarbon nanotubesGas sensingVanadium oxideArticleChimowa, G., Tshabalala, Z. P., Akande, A. A., Bepete, G., Mwakikunga, B. W., Ray, S. S., & Benechada, E. (2017). Improving methane gas sensing properties of multi-walled carbonnanotubes by vanadium oxide filling. http://hdl.handle.net/10204/10167Chimowa, George, Zamaswazi P Tshabalala, Amos A Akande, G Bepete, Bonex W Mwakikunga, Suprakas S Ray, and EM Benechada "Improving methane gas sensing properties of multi-walled carbonnanotubes by vanadium oxide filling." (2017) http://hdl.handle.net/10204/10167Chimowa G, Tshabalala ZP, Akande AA, Bepete G, Mwakikunga BW, Ray SS, et al. Improving methane gas sensing properties of multi-walled carbonnanotubes by vanadium oxide filling. 2017; http://hdl.handle.net/10204/10167.TY - Article AU - Chimowa, George AU - Tshabalala, Zamaswazi P AU - Akande, Amos A AU - Bepete, G AU - Mwakikunga, Bonex W AU - Ray, Suprakas S AU - Benechada, EM AB - Manipulation of electrical properties and hence gas sensing properties of multi-walled carbon nanotubes (MWNTs) by filling the inner wall with vanadium oxide is presented. Using a simple capillary technique, MWNTs are filled with vanadium metal which is later oxidized. It is observed that the methane gas detection response time at room temperature (293 K), is significantly improved from 138 s (in vanadium pentoxide) to 16 s (in filled MWNTs) while the recovery times changes from 234 s to 120 s respectively. The response sensitivity of the unfilled CNTs is improved from 0.5% to 1.5% due to the metal oxide filling. Using theoretical Density Functional Theory (DFT) electronic structure calculations, we show that the enhanced response is due to the increased density of states around the Fermi level of the composite material as a result of the encapsulated metal oxide. And we propose an adsorption mechanism at three different sites of the MWNTs surface based on the Langmuir model. This work also highlights the influence of ambient oxygen in carbon nanotube based sensors, an aspect that has not been clearly addressed in many previous theoretical and experimental studies. DA - 2017-08 DB - ResearchSpace DP - CSIR KW - Carbon nanotubes KW - Gas sensing KW - Vanadium oxide LK - https://researchspace.csir.co.za PY - 2017 SM - 0925-4005 T1 - Improving methane gas sensing properties of multi-walled carbonnanotubes by vanadium oxide filling TI - Improving methane gas sensing properties of multi-walled carbonnanotubes by vanadium oxide filling UR - http://hdl.handle.net/10204/10167 ER -