Increased reactivity of single wall carbon nanotubes at carbon ad-dimer defect sites

A quantum chemical study of the reactivity of the 7-5-5-7 topological defect, corresponding to a carbon ad-dimer, on a (5, 5) armchair nanotube is reported. The energies indicate that the defect is more reactive by 46–70 kcal/mol towards adsorbates containing π-bonds, such as C2H4, O2, and O3, than are pristine nanotubes or the Stone–Wales 5-7-7-5 defect. The enhanced reactivity of this defect was also obtained for other sizes and types of carbon nanotubes.