On the control of carbon nanostructures for hydrogen storage applications

The storage of hydrogen in different carbon nanostructures has been investigated using classical Monte-Carlo simulations techniques. Very low hydrogen uptakes (?1% wt) have been calculated for single-walled and double-walled carbon nanotubes, as well as for graphite nanofibers at 293 K and 10 MPa. The amount of hydrogen uptake strongly depends on the porosity within the nanostructure network where optimal arrangements give rise to the formation of a well-defined two-dimensional adsorbed hydrogen layer. The presence of metallic impurities within single-walled nanotube bundles was modeled by disseminating atomic particles, characterized by a highly attractive potential, throughout the nanotube network. It has been found that the presence of metallic particles significantly enhances the hydrogen uptake, but not to a point where this could be considered a promising storage solution.