Chimowa, GeorgeMatsoso, BCoville, NJRay, Suprakas SFlahaut, EHungria, TDatas, LMwakikunga, Bonex W2018-05-112018-05-112017-06Chimowa, G., Matsoso, B., Coville, N.J. et al. 2017. Preferential adsorption of NH3 gas molecules on MWCNT defect sites probed using in situ Raman spectroscopy. Physica Status Solidi A- Applications and Materials Science, vol. 214(10): DOI 10.1002/pssa.2016009301862-63001862-6319https://onlinelibrary.wiley.com/doi/full/10.1002/pssa.201600930DOI 10.1002/pssa.201600930http://hdl.handle.net/10204/10187Copyright: 2017 Wiley. 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 preferential adsorption of NH(sub3) gas molecules on multi-walled carbon nanotubes (MWCNTs) was studied using in situ Raman spectroscopy. It was observed that the full widths at half maximum of the G band and the intensity ratio I(sub2D)/I(subG) of the MWCNTs decreased significantly during NH(sub3) gas adsorption at elevated temperatures. These observations were explained in terms of suppressed second-order-defect associated Raman vibrations resulting in a lower disorder Raman band due to ammonia adsorption on the defect sites. Another corresponding effect was a temporary increase in electron doping levels due to ammonia adsorption. This behaviour was accompanied by a drop of ca. 2% in the resistance of the MWCNTs corresponding to the occupancy of most of the defect sites. We suggest preferential adsorption of ammonia gas molecules on the thermally activated defect sites of MWCNTs as an appropriate gas sensing mechanism. This knowledge can be used to design and tune the selectivity of ammonia gas sensors.enAdsorptionCarbon nanotubesGas sensingRaman spectroscopyArticleChimowa, G., Matsoso, B., Coville, N., Ray, S. S., Flahaut, E., Hungria, T., ... Mwakikunga, B. W. (2017). Preferential adsorption of NH3 gas molecules on MWCNT defect sites probed using in situ Raman spectroscopy. http://hdl.handle.net/10204/10187Chimowa, George, B Matsoso, NJ Coville, Suprakas S Ray, E Flahaut, T Hungria, L Datas, and Bonex W Mwakikunga "Preferential adsorption of NH3 gas molecules on MWCNT defect sites probed using in situ Raman spectroscopy." (2017) http://hdl.handle.net/10204/10187Chimowa G, Matsoso B, Coville N, Ray SS, Flahaut E, Hungria T, et al. Preferential adsorption of NH3 gas molecules on MWCNT defect sites probed using in situ Raman spectroscopy. 2017; http://hdl.handle.net/10204/10187.TY - Article AU - Chimowa, George AU - Matsoso, B AU - Coville, NJ AU - Ray, Suprakas S AU - Flahaut, E AU - Hungria, T AU - Datas, L AU - Mwakikunga, Bonex W AB - The preferential adsorption of NH(sub3) gas molecules on multi-walled carbon nanotubes (MWCNTs) was studied using in situ Raman spectroscopy. It was observed that the full widths at half maximum of the G band and the intensity ratio I(sub2D)/I(subG) of the MWCNTs decreased significantly during NH(sub3) gas adsorption at elevated temperatures. These observations were explained in terms of suppressed second-order-defect associated Raman vibrations resulting in a lower disorder Raman band due to ammonia adsorption on the defect sites. Another corresponding effect was a temporary increase in electron doping levels due to ammonia adsorption. This behaviour was accompanied by a drop of ca. 2% in the resistance of the MWCNTs corresponding to the occupancy of most of the defect sites. We suggest preferential adsorption of ammonia gas molecules on the thermally activated defect sites of MWCNTs as an appropriate gas sensing mechanism. This knowledge can be used to design and tune the selectivity of ammonia gas sensors. DA - 2017-06 DB - ResearchSpace DP - CSIR KW - Adsorption KW - Carbon nanotubes KW - Gas sensing KW - Raman spectroscopy LK - https://researchspace.csir.co.za PY - 2017 SM - 1862-6300 SM - 1862-6319 T1 - Preferential adsorption of NH3 gas molecules on MWCNT defect sites probed using in situ Raman spectroscopy TI - Preferential adsorption of NH3 gas molecules on MWCNT defect sites probed using in situ Raman spectroscopy UR - http://hdl.handle.net/10204/10187 ER -