GRAND CANONICAL MONTE CARLO SIMULATION OF HYDROGEN ADSORPTION IN DIFFERENT CARBON NANOSTRUCTURES

摘要

Grand canonical Monte Carlo (GCMC) simulations are performed to study hydrogen physisorp-tion in different nanocarbon porous materials made up of different substructures including carbon nanotubes (CNTs), graphene sheets, and C60. Hydrogen weight percentage (wt%) at different temperatures with pressure ranging from 1 to 20 MPa 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 of the present study agree well with other available computational data. It is found that CNT arrays, graphite nanofibers (GNFs), and C60 intercalated graphite (CIG) can reach a hydrogen storage weight percent as high as only 3% at room temperature and 20 MPa when equilibrium sub-structural spacing values are used. The quantum effect is significant in low-temperature hydrogen adsorption simulation, and the particular scheme to include the quantum effect predicts the magnitude of weight percent to vary as much as 3.5%.