Cycloaddition of ethene on a series of single-walled carbon nanotubes

The binding energy of ethene to several (n,0) and (n,n) single wall carbon nanotubes where n = 5–9 are investigated by B3LYP density functional theory (DFT). The calculated binding energies indicate the cycloaddition reactions to be exothermic for the smaller diameter nanotubes (5,0) and (6,0) and increasingly endothermic as the diameter of the nanotube increases. The binding energy of ethene to the smallest SWCNT of this work, the (5,5) SWCNT, is exothermic and increasingly endothermic as n increases for the remaining (n,n) SWCNTs. Bonding alters the hybridization of the CC bonds of both the ethene and the C atoms of the nanotube to which the ethene is bound. The HOMO and LUMO orbitals include the ethene and are delocalized over the length of the tube.