  Grand Canonical Monte Carlo (GCMC) simulations are performed to study
hydrogen physisorption in different nano carbon porous materials made up of
different substructures including carbon nanotubes (CNT), graphene sheets and
C60. Hydrogen weight percentage (wt%) at different temperatures with pressure
ranging from 1 to 20MPa are predicted. Fugacity and quantum effects on hydrogen
adsorption are investigated. Different structural dimensions including the
sizes of the substructures and spacing between the substructures are used to
study the geometrical effects on hydrogen storage capacity in carbon materials.
The calculated results generally agree well with available data from other
calculations. It is concluded that CNT arrays, graphite nanofibers (GNF) and
C60 intercalated graphite (CIG) are not promising to reach the DOE 6.5 wt%
target at room temperature. It is also found that the quantum effect is
significant in low temperature hydrogen adsorption and different treatments to
account for the quantum effect also influence the predicted wt% differently.
