Hydrogen adsorption in carbon nanostructures

Hydrogen adsorption, (BET) specific surface area and X-ray diffraction (XRD) measurements have been performed on carbon nanofibers, intercalated and exfoliated carbon materials. Excess adsorption capacity was evaluated at equilibrium pressures and temperatures ranging from 0.1 to 10.5 MPa and 77 to 295 K, respectively. We find that at room temperature, carbon nanofibers can adsorb up to 0.7 wt% at 10.5 MPa. We observed that the presence of different nickel-copper ratios in the catalyst particles leads to change in crystalline structure and specific surface area. Furthermore, we noted that the latter can be increased by the addition of hydrogen in the organic gas during the synthesis of the nanofibers. Finally, we will discuss the hydrogen coverage per unit surface area which is substantially larger on nanostructures than on activated carbon. (C) 2001 International Association for Hydrogen Energy. Published by Elsevier Science Ltd. All rights reserved.