Hydrogen storage by decalin/naphthalene pair and hydrogen supply to fuel cells by use of superheated liquid-film-type catalysis

A catalytic reaction pair of decalin dehydrogenation/naphthalene hydrogenation has been proposed as a storage medium for fuel-cell hydrogen in mobile modes. The hydrogen capacities with decalin (7.3 wt.%, 64.8 kg-H-2 m(3)) are higher than the target values of the Department of Energy, USA (6.5 wt.%, 62.0 kg-H-2 m(3)). Platinum-rhenium composite catalysts supported on granular activated carbon in superheated liquid-film states gave excellent reactivities for decalin dehydrogenation, where the conversion of almost 100% from decalin to naphthalene was attained within I h by heating at 280 degrees C in a batch-wise reactor. Superheated liquid-film conditions were also realized in a continuous-type reactor at the same temperature (280 degrees C). With the goal of maintaining rapid evolution of hydrogen stationarily, a rather wide range of decalin feed rates was allowable with use of platinum particles supported on activated carbon cloth. Decalin should be evaluated as an organic chemical hydride not only because of its storage densities but also because of its potential power densities for fuel-cell vehicles. (c) 2005 Elsevier B.V. All rights reserved.