Discussion Topic Posted for the NANOTUBE-99 Workshop:

It is not surprising that Nuetzenadel et al. were not able to store large amounts of hydrogen through gas-phase physisorption. We have performed a series of computer simulations of hydrogen adsorption on various carbon nanotubes and have found that the amount adsorbed is very low at room temperature, around 0.1 wt% at 10 atm, and about 0.8 wt% at 100 atm [1]. Even if the geometry of the nanotube array is treated as an adjustable parameter, the amount of hydrogen adsorbed is still quite low [2]. Comparison of hydrogen adsorption in carbon nanotubes and in graphitic slit pores indicates that the slit pore geometry is better suited to hydrogen storage than the tubular geometry [1].

We have also simulated hydrogen adsorption on graphitic nanofibers in an attempt to reproduce the remarkable results obtained by the Rodriguez group [3]. Our results demonstrate that the amount of adsorption that Rodriguez et al. claim to observe cannot possibly be the result of physisroption of hydrogen on the graphitic nanofibers [4].

References:

[1] Q. Wang and J.K. Johnson, J. Chem. Phys. 110, 577 (1999).
[2] Q. Wang and J.K. Johnson, submitted to J. Phys. Chem. B (1999).
[3] A. Chambers, C. Park, R.T.K. Baker, and N.M. Rodriguez, J. Phys. Chem. B 102, 4253 (1998).
[4] Q. Wang and J.K. Johnson, J. Phys. Chem. B 103, 281 (1999).

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