Preparation and characterization of carbonaceous material-based hydrogen absorbing composites

Synthesis of hydrogen sorbing composites was attempted by ball milling under hydrogen atmosphere with graphite, carbon black, zirconium metal and ZrMn2 alloy employed as starting materials. The milling of graphite increased specific surface areas with milling time, but the increase in specific surface area did not monotonously increase the hydrogen capacity. Only zirconium-carbon black composite sorbed more hydrogen than expected for a mere mixture with the same composition. The higher hydrogen capacity on the zirconium-carbon black composite would be due to the specific sites on the carbonaceous material created during the milling. Another effect of the composite formation was stabilization of zirconium and ZrMn2, that is, higher temperatures were required to completely dehydrogenate the composites and the ZrMn2-carbonaceous composites did not ignite in air. (C) 2003 Elsevier B.V. All rights reserved.