Gas adsorption on heterogeneous single-walled carbon nanotube bundles.

Optimization of carbon nanotube bundles containing a distribution of nanotube diameters always gives structures with packing defects that form relatively large interstitial channels. Experimental data for CH4, Ar, and Xe adsorption are compared with simulations. Low coverage experimental isosteric heats are in excellent agreement with simulations of gases adsorbing into interstitial channels of defective nanotube bundles, whereas adsorption onto perfect bundles does not agree with experiments. Thus, an accurate description of adsorption on nanotube bundles must account for interstitial adsorption.