Molecular simulation of xenon adsorption on single-walled carbon nanotubes

摘要

Adsorption of xenon on single-walled (10,10) carbon nanotubes at a temperature of 95 K has been studied by molecular simulation and the results have been compared with recent experiments [A. Kuznetsova, J. T. Yates, Jr., I. Liu, and R. B. Smalley, I. Chem. Phys. 112, 9590 (2000)]. Simulations indicate that adsorption takes place primarily on the inside of the nanotubes at the experimental conditions. Interstitial and external adsorption were found to be negligible in comparison with adsorption inside the nanotubes. The coverage computed from simulation of 0.06 Xe—C is in good agreement with the experimentally measured value of 0.042 Xe—C. The isosteric heat of adsorption from simulation ranges from about 3000 to 4500 K as a function of coverage, which is consistent with the experimental desorption activation energy of 3220 K. Adsorption on the external surfaces of the nanotubes is observed to take place at Xe pressures that are larger than those probed in the experiments. The good agreement between simulations and experiments for the coverage and heat of adsorption indicate that the curvature of the nanotube does not substantially perturb the adsorption potential from that of a graphene sheet.