Determination of the binding energy of methane on single-walled carbon nanotube bundles

Low-coverage adsorption isotherms for ${\mathrm{CH}}_4$ on single-walled carbon nanotube bundles have been measured at eight temperatures between 155 and 195 K. The nanotubes used in this study were untreated, so that the tubes have closed ends. The isosteric heat of adsorption was determined from the isotherms and, from this quantity, the binding energy of the methane on the nanotube substrate was obtained. The binding energy was found to be 76% larger on the nanotube bundles than it is on planar graphite.