Molecular hydrogen interacting with Si-, S- and P-doped C ₆₀ fullerenes and carbon nanotube

Density functional theory calculations were used to investigate the hydrogen storage capacity of Si, S and P-doped C ₆₀ fullerenes and carbon nanotubes (CNTs). Binding energies are calculated and hydrogen binding to the dopant substrates is compared. Our results indicate that all the dopant atoms form stable bindings with the considered nanocage and nanotube. It was found that up to eight hydrogen molecules being adsorbed on the S-doped CNT can form the stable complex while for the Si-doped C ₆₀ the maximum number of hydrogen molecules being attached to the dopant atom was estimated to be six. The hydrogen storage capacity of C ₆₀ fullerene coated with 6 Si atoms show that up to 36 H ₂ molecules can be stored on the nanocage, resulting in gravimetric densities of hydrogen of 7.5%. Furthermore, incorporation of the hydrogen molecule into the respected nanoparticles has been investigated and the obtained results reveal that hydrogen molecules prefer to be adsorbed on the exterior surface of the doped substrate in comparison to the interior sidewall.