Reactivity of the interior surface of (5,5) single-walled carbon nanotubes with and without a Stone–Wales defect

The adsorption of hydrogen and fluorine atoms on the interior surface of defect-free and Stone–Wales defect armchair (5,5) single-walled carbon nanotubes were investigated using density functional theory. The reaction energy values for the hydrogenation and fluorination at all the possible unique sites were obtained at the UB3LYP/6-31G* level. The calculated reaction energy values were used to corroborate the reactivities of different sites on the interior surface of SWCNTs. The results indicate that for defect-free nanotube, endohedral adsorption is rather unfavorable both for hydrogen and fluorine. The computed exothermicities range from 4.8 to 13.4 kcal/mol for hydrogenation and from 16.6 to 23.2 kcal/mol for fluorination. However, the introduction of a SW defect on the (5,5) SWCNT improves the chemical reactivity of the interior surface of the defected tube. The computed exothermicities for the endohedral hydrogen and fluorine atoms are within the ranges of 7.0–33.4 and 18.5–41.8 kcal/mol, respectively. The most exothermic and reactive site on the interior surface of SW defective (5,5) SWCNT is the C2 site shared by two seven-membered rings and one five-membered ring. This is different from the results reported on the reactivity of the exterior surface of SW defective nanotubes. The electronic and vibrational properties of the (5,5) SWCNTs with adsorption of hydrogen and fluorine atoms on the interior surface were also explored.