Functionalization of Carbon Nanotubes Using Nitric Acid Oxidation and DBD Plasma

In this study, multiwall carbon nanotubes (MWNTs) were modified with nitric acid chemically and by dielectric barrier discharge (DBD) plasma in an oxygen-based atmosphere. Used carbon nanotubes (CNTs) were prepared by chemical vapour deposition (CVD) floating catalyst method. For removing amorphous carbon and metal catalyst, MWNTs were exposed to dry air and washed with hydrochloric acid. Heating purified CNTs under helium atmosphere caused elimination of acidic functional groups. Fourier transformed infrared spectroscopy (FTIR) shows formation of oxygen containing groups such as C=O and COOH. Brunauer, Emmett, Teller (BET) analysis revealed that functionalization causes generation of defects on the sidewalls and opening of the ends of CNTs. Results of temperature-programmed desorption (TPD) and gas chromatography(GC) indicate that nitric acid treatment create more acidic groups than plasma treatment.




References:
[1] S. Iijima, "Helical microtubules of graphitic carbon," Nature, vol. 354,
pp. 56, 1991.
[2] S. Chen, W. She, G. Wu, D. Chen, and M. Jiang, "A new approach to the
functionalization of single-walled carbon nanotubes with both alkyl and
carboxyl groups," Chemical Physics Letters, vol. 402, pp. 312-317,
2005.
[3] P. Serp, M. Corrias, and P. Kalck, "Carbon nanotubes and nanofibers in
catalysis," Applied Catalysis A: General, vol 253, pp. 337-358, 2003.
[4] M. Fleischer, and H. Meixner, "Selectivity in high-temperature operated
semiconductor gas-sensors," Sensors and Actuators B, vol. 52, pp. 179-
187, 1998.
[5] A. M. Shanmugharaj, J. H. Bae, and K.Y. Lee, "Physical and chemical
characteristics of multiwalled carbon nanotubes functionalized with
aminosilane and its influence on the properties of natural rubber
composites," Composites Science and Technology, vol. 67, pp. 1813-
1822, 2007.
[6] W. Xia, Y. Wang, R. Bergstra, S. Kundu, and M. Muhler, "Surface
characterization of oxygen-functionalized multi-walled carbon
nanotubes by high-resolution X-ray photoelectron spectroscopy and
temperature-programmed desorption," Applied Surface Science, vol.
254, pp. 247-250, 2007.
[7] T. Kyotani, S. Nakazaki, W. Xu, and A. Tomita, "Chemical modification
of the inner walls of carbon nanotubes by HNO oxidation," Carbon, vol.
39, pp. 771 -785, 2001.
[8] T. Xu, J. Yang J. Liu, and Q. Fu, "Surface modification of multi-walled
carbon nanotubes by O2 plasma," Applied SurfaceScience, vol. 253, pp.
8945-8951, 2007.
[9] R. Ionescu, E. H. Espinosa, E. Sotter, E. Llobet, X. Vilanova, X.
Correig, A. Felten, C. Bittencourt, G. Van Lier, J. C. Charlier, and J.J.
Pireaux, " Oxygen functionalisation of MWNT and their use as gas
sensitive thick-film layers," Sensors and Actuators B, vol. 113, pp. 36-
46, 2006.
[10] M. A. Montes-Moran, D. Suarez, J. A. Menendez, and E. Fuente, "On
the nature of basic sites on carbon surfaces: An overview," Carbon, vol.
42, pp. 1219-1225, 2004.
[11] Y. Li, S. Wang, Z. Luan, J. Ding, C. Xu and D. Wu, "A dsorption of
cadmium(II) from aqueous solution by surface oxidized carbon
nanotubes," Carbon, vol. 41, pp. 1057-1062, 2003.
[12] B. Rurlle, S. Peeterbroeck, R. Gouttebaron, T. Godfroid, F. Monteverde,
J. Dauchot, M. Alexandre, M. Hecq, and P. Dubois, "Functionalization
of carbon nanotubes by atomic nitrogen formed in a microwave plasma
Ar +N2 and subsequent poly grafting," Journal of Materials Chemistry,
vol. 17, pp. 157-159, 2007.
[13] C. Zhao, L. Ji, H. Liu, G. Hu, S. Zhang, M. Yang, and Z. Yang,
"Functionalized carbon nanotubes containing isocyanate groups,"
Journal of Solid State Chemistry, vol. 177, pp.4394-4398, 2004.
[14] D. B. Mawhinney, V. Naumenko, A. uznetsova, and J. T. Yates,
"Infrared Spectral Evidence for the Etching of Carbon Nanotubes:
Ozone Oxidation at 298 K," J. Am. Chem. Soc, vol. 122, pp. 2383-2384,
2000.
[15] P. Chingombe, B. Saha, and R. J. Wakeman, "Surface modification and
characterization of a coal-based activated carbon," Carbon, vol. 43, pp.
3132-3143, 2005.
[16] H. P. Boehm, "Surface oxides on carbon and their analysis: a critical
assessment," Carbon, vol. 40, pp.145 -149, 2002.
[17] S. Tsang, Y. Chen, P. Harris, and M. Green, "A simple chemical method
of opening and filling carbon nanotubes," Nature, vol.372, pp.159, 1994.
[18] S. Banerjee, T. Hemraj and S. Wong, "Covalent surface chemistry of
single-walled carbon nanotubes," Adv. Mater, vol. 1, pp. 17, 2005.