Desorption kinetics and interaction of Xe with single-wall carbon nanotube bundles

We present a study on the kinetics of xenon desorption from single-wall carbon nanotube (SWNT) bundles using thermal desorption spectroscopy (TDS). Desorption features from SWNT samples are broadened and peaked at higher temperature if compared to graphite. This can be explained using a coupled desorption–diffusion (CDD) model, which yields the low-coverage binding energy for Xe adsorption on SWNT bundles, 27 kJ mol−1. The latter is about 25% higher than the monolayer binding energy on graphite, 21.9 kJ mol−1. Using molecular mechanics calculations we find that this increase is consistent with adsorption in highly coordinated groove-sites on the external bundle surface or in endohedral sites inside of SWNTs.