Room temperature hydrogen uptake of carbon nanotubes promoted by silver metal catalyst

Hydrogen adsorption studies of silver-embedded carbon nanotubes (Ag/CNTs) synthesized by in situ reduction method were performed at 298K and hydrogen equilibrium pressure of 23 atm. The saturated reversible hydrogen storage capacity exhibited by silver embedded carbon nanotubes is found to be 0.86wt.% which is nearly 40% more as compared to the hydrogen uptake of purified carbon nanotubes measured under similar experimental conditions. The enhanced hydrogen storage capacity of carbon nanotubes is attributed to the spillover of physisorbed hydrogen from silver nanoparticles. The hydrogen uptake by Ag/CNT samples follows the Henry's rule, suggesting that there is no significant adsorbate-adsorbate interaction in the low-pressure region. XRD spectrum indicated that 32% increase in particle size was observed in hydrogenated samples as compared to non-hydrogenated samples. (C) 2008 Elsevier B.V. All rights resented.