Computer simulation of the fracture of carbon nanotubes in a hydrogen environment

Molecular dynamics simulations have been performed to study the mechanical properties of armchair-type single-walled and multiple-walled carbon nanotubes under tensile loading with and without hydrogen storage. Advanced bond order potentials were used in the simulations. Hydrogen molecules stored inside or outside nanotubes reduced the fracture strength of nanotubes. During the deformation, some C-C bonds were broken and reconstructed. If hydrogen. molecules were around, hydrogen atoms would compete with the carbon atoms, to form the H-C bonds, which reduces the mechanical strength of nanotubes. Such detrimental effect of hydrogen is enhanced if the curvature of the tubes is increased, or if hydrogen is stored in a multiple-walled carbon nanotube.