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Carbon as a high capacity solid state storage medium for hydrogen

Graphite nanofibers were synthesized and their hydrogen desorption and adsorption properties are reported for temperatures of 77 and 300 K. Catalysts were made by several different methods including chemical routes, mechanical alloying and gas condensation. The nanofibers were grown by passing ethylene and H/sub 2/ gases over the catalysts at 600/spl deg/C. Hydrogen desorption and adsorption were measured using a volumetric analysis Sieverts' apparatus, and the graphite nanofibers were characterized by transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) surface area analysis. The absolute level of hydrogen desorption measured from these materials was typically less than 0.01 H/C atom, comparable to other forms of carbon.