A grand canonical Monte Carlo study of hydrogen adsorption in carbon nanohorns and nanocones at 77 K

Abstract

H 2 adsorption in carbon nanohorns and nanocones has been simulated at 77 K using the grand canonical Monte Carlo method. The models used for the solid adsorbents were nanosized curved graphene sheets of conical shape with five different apex angles, corresponding to the introduction of 1–5 pentagons to the hexagonal carbon network; nanohorns are a subclass of the carbon cone family (5 pentagons). Hydrogen molecules have been treated as Lennard-Jones spherical particles with quantum behavior. Details of the adsorption process have been revealed by studying carefully the cone–hydrogen interactions as well as the adsorption capacities and energies, in cones of different dimensions. Additionally, for comparison purposes similar studies have been carried out for carbon nanotube model structures and the effect of pore shape/size as well as elements of the role of confinement on sorption have been highlighted.