Adsorption and dissociation of hydrogen molecules on a Pt atom on defective carbon nanotubes

Using density functional calculations, we investigate the catalytic effect of a Pt atom on a defective carbon nanotube. The Pt atom binds more strongly to the vacancy site than to the Stone-Wales defect and to the pure surface of the nanotube. The binding energy of the H-2 molecule on the vacancy is significantly reduced to 0.69 eV from 1.26 eV of the pure (5,5) nanotube but still sufficient enough to maintain minimum bond strength on the Pt atom. Moreover, the H-H distance is separated to 2.16 angstrom. The feasibility to the fuel cell is further discussed. (c) 2008 American Institute of Physics.