Grand Canonical Monte Carlo simulations of the hydrogen storage capacities of slit-shaped pores, nanotubes and torusenes

Abstract

Grand Canonical Monte Carlo, GCMC, simulations are used to study the gravimetric and volumetric hydrogen storage capacities of different carbon nanopores shapes: Slit-shaped, nanotubes and torusenes at room temperature, 298.15 K, and at pressures between 0.1 and 35 MPa, and for pore diameter or width between 4 and 15 Å. The influence of the pore shape or curvature on the storage capacities as a function of pressure, temperature and pore diameter is investigated and analyzed. A large curvature of the pores means, in general, an increase of the storage capacities of the pores. While torusenes and nanotubes have surfaces with more curvature than the slit-shaped planar pores, their capacities are lower than those of the slit-shaped pores, according to the present GCMC simulations. Torusene, a less studied carbon nanostructure, has two radii or curvatures, but their storage capacities are similar or lower than those of nanotubes, which have only one radius or curvature. The goal is to obtain qualitative and quantitative relationships between the structure of porous materials and the hydrogen storage capacities, in particular or especially the relationship between shape and width of the pores and the hydrogen storage capacities of carbon-based porous materials.