No 4, Vol. 5, 2004 
 

DESORPTION BEHAVIOR OF GASEOUS MOLECULES ON SINGLE-WALLED CARBON NANOTUBE BUNDLES

B.Y. Wei1, H.M. Lin1, Y.S. Yang2, H.J. Lai3 and S.H. Chien1

1 Department of Materials Engineering, Tatung University, 40 ChungShan N. Rd.,
Sec. 3, Taipei 104, Taiwan
2 Institute of Chemistry, Academia Sinica, Taipei 11529, Taiwan
3 Materials Research Laboratories, Industrial Technology Research Institute,
Hsinchu 310, Taiwan

Abstract

Temperature programmed desorption (TPD) technology was used to examine desorption activation energies (Ed) of O2, N2 and Ar on single-walled carbon nanotube (SWCNT) bundles. The SWCNT bundles obtained from Carbon Nanotechnologies Inc. were prepared by high-pressure CO (HiPco) disproportionation process, and had diameters of approximately 0.8 nm. The results show that the temperatures at which the maximum desorption rates of O2, N2 and Ar on SWCNTs are all below 200 °C, and the corresponding Ed values are 209, 192 and 188 meV, respectively. The Ed values are very close to the isosteric heat of adsorption (qst) obtained from our previous studies, implying that these gases are physisorbed onto SWCNTs.

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