Role of surface chemistry in hydrogen adsorption in single-wall carbon nanotubes

A combination of tight-binding molecular dynamics and grand-canonical-ensemble Monte Carlo is used to model adsorption of molecular hydrogen in chemically modified matrices of single-wall carbon nanotubes. We study the effects of chemical modification of the nanotube surface by including different coverages of chemisorbed atomic hydrogen and surface oxidation by removing islands of missing carbon atoms with H-saturated bonds. Chemisorbed hydrogen reduces the gas storage capabilities of carbon nanotubes, while the opening of cavities by oxidation tends to increase the mass of stored hydrogen gas in terms of both gravimetric and volumetric capacity.