Theoretical Study of the Relationship Between the Electronic Structure of Carbon Nanotube Surface and Its Hydrogenation Sites

The activation energy of radical addition to polycyclic aromatic carbons consisting of only six-membered rings decreases with increasing curvature. In this study, the position of monohydrogenation in carbon nanotubes containing five- and six-membered carbon rings was investigated through density functional theory calculations. The activation energies of the monohydrogenation of carbon at the intersection of three six-membered rings were 2.0-2.8 kcal mol(-1), and those of carbon-containing one five-membered ring were close to zero. Bonding sites involving a five-membered ring were found to have lower deformation energies for becoming sp(3)-like, and induced stronger interactions with hydrogen atoms.