The interaction of H2 molecules with multi-vacancy defects in single-wall carbon nanotubes and their subsequent incorporation were investigated using density-functional theory calculations and molecular dynamic simulations. The stability of multivacancies in (8,8) carbon nanotube was examined, with n the number of missing atoms (n = 2 to 16). It was found that 16V was the limiting size, where defect reconstruction was unlikely; preserving the unsaturated border. Following hydrogenation, the border was passivated leaving an inert pore about 6Å in diameter. It was verified that the incorporation and release of H2 molecules through this nanopore was barrier-less and its stability in contact with a H2 gas for both exohedral and endohedral adsorptions was preserved at high temperatures. Also found were endohedral binding energies of 0.14 to 0.21eV/H2 at room temperature. These were close to those which were estimated to be optimum for a reversible adsorption-desorption process, suggesting that nanoporous carbon nanotubes as produced by electron irradiation in a hydrogen atmosphere could be an effective H2 storage medium, allowing the access to the carbon nanotube inner space.

Reaction and Incorporation of H2 Molecules Inside Single-Wall Carbon Nanotubes through Multivacancy Defects. W.Orellana: Physical Review B, 2009, 80[7], 075421