Preferential adsorption of NH3gas molecules on MWCNT defect sites probed usingin situRaman spectroscopy

Physica Status Solidi (A) Applications and Materials Science - Tập 214 Số 10 - 2017
George Chimowa1,2, Boitumelo J. Matsoso3, Neil J. Coville3, Suprakas Sinha Ray2,4, Emmanuel Flahaut1, Teresa Hungrı́a5, Lucien Datas1,5, Bonex Mwakikunga2
1CIRIMAT, Université de Toulouse, CNRS, INPT, UPS, UMR CNRS‐UPS‐INP N°5085, Université Toulouse 3 Paul Sabatier Bât. CIRIMAT 118, route de Narbonne 31062 Toulouse cedex 9 France
2DST/CSIR National Centre for Nano‐Structured Materials Council of Scientific and Industrial Research P.O. Box 395 Pretoria 0001 South Africa
3DST/NRF Centre of Excellence in Strong Materials and the Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg, WITS 2050, South Africa
4Department of Applied Chemistry, University of Johannesburg, Doornfontein, 2028 Johannesburg, South Africa
5UMS 3623, Centre de microcaractérisation Raimond Castaing Université de Toulouse 3 rue Caroline Aigle 31400 Toulouse France

Tóm tắt

The preferential adsorption of NH3gas molecules on multi‐walled carbon nanotubes (MWCNTs) was studied usingin situRaman spectroscopy. It was observed that the full widths at half maximum of the G band and the intensity ratioI2D/IGof the MWCNTs decreased significantly during NH3gas 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 ofca. 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.

Từ khóa


Tài liệu tham khảo

10.1016/j.snb.2011.08.032

10.1007/s40820-014-0023-3

Basu S., 2009, J. Sens, 2009, 861968, 10.1155/2009/861968

10.1016/j.snb.2013.03.128

10.1038/srep01868

10.1021/ja207285b

10.1016/j.snb.2017.02.167

10.1016/j.snb.2012.10.106

10.1007/s10853-016-0491-6

10.1186/1556-276X-7-173

10.1155/2012/904323

Wang Y., 2009, J. Sens, 493904, 10.1155/2009/493904

10.3390/s130708814

10.1016/S0925-4005(01)00923-6

10.1016/j.physrep.2004.10.006

10.1016/j.snb.2012.11.014

10.1088/0957-4484/19/33/332001

10.1063/1.1424069

10.1016/S0925-4005(01)00938-8

10.1016/S0925-4005(00)00598-0

S. W.GayandK. F.Knowlton Virginia Cooperative Extension publication442 110(2005).

10.1016/j.vibspec.2012.02.007

10.1016/j.ssc.2007.03.052

10.1021/nl201432g

10.1103/PhysRevLett.97.187401

Bradley M., Multiplying Productivity: The Nicolet iZ10 module

Wang Z. L., 2003, Nanowires and Nanobelts, Materials, Properties and Devices, Metals and Semiconductor Nanowires, 57, 10.1007/978-0-387-28745-4

Thông tin
Thông tin xuất bản

Physica Status Solidi (A) Applications and Materials Science

Tập 214 Số 10

Thông tin tác giả