DIRECT MEASUREMENT OF BINDING ENERGY VIA ADSORPTION OF METHANE ON SWNT

摘要

Low coverage adsorption isotherms for CH_4 on single-walled carbon nanotubes have been measured at various temperatures between 144 and 184 K. The nanotubes used in this study were untreated; hence, they remain capped. Adsorption takes place preferentially in the interstitial channels between the individual SWNT strands which constitute nanotube bundles. The isosteric heat of adsorption for methane on the nanotubes has been obtained from the isotherm results. The isosteric heat is directly related to the binding energy of CH_4 to the nanotube substrate; the binding energy of methane in the interstitial channels of the SWNT's was determined to be 226 meV. This value of the binding energy is 80% larger than the reported value for the binding energy for methane on planar graphite.