Toward an Accurate Description of Methane Physisorption on Carbon Nanotubes

We
present a high-level ab initio investigation of the effects of model
size and curvature on the exterior and interior binding energy of
methane on single-walled carbon nanotubes. The interaction energies
of methane with curved coronene were computed using complete basis
set MP2 with a CCSD­(T) correction. A variety of novel dispersion-including
density functional approaches were then compared to the benchmark
data. The top-performing functionals were used to calculate binding
energies between methane and larger nanotube fragments all the way
through infinite nanotubes. The methane binding energy of a narrow
(9,0) carbon nanotube, compared to a flat graphene surface, is decreased
by 32% on the exterior but increased by 185% on the interior.