Density Functional Theory and Grand Canonical Monte Carlo Simulations of the Hydrogen Storage Properties of Partially Truncated and Open Cage C₆₀ Fullerenes

The potential energies of H₂ molecules with partially truncated and open cage C₆₀ fullerenes, including C₅₈, C₅₅, C₅₄(I), C₅₄(II) and C₄₆, are investigated by means of the density functional theory method. The energy barrier for one H₂ molecule (with two postures) entering into the nanocage decreases from 435.59 (513.45) kcal/mol to 3.64 (−2.06) kcal/mol with the increase of the truncated pore. The grand canonical Monte Carlo simulations reveal that each nanocage can accommodate only one H₂ molecule inside its cavity at both 77 K and 298 K. All the other H₂ molecules are adsorbed round the truncated pores outside the nanocages. Exceptionally, the truncated C₄₆ can store 2.28wt% H₂ molecules at 77 K. Therefore, the truncating part of the C₆₀ molecule may be a novel idea to explore C₆₀ fullerene as a hydrogen storage material.