In a closed pressure vessel, the reaction of sodium borohydride (NaBH4) with Pt-LiCoO2 catalyst and a stoichiometric amount of water drastically increases the pressure owing to the generation of large quantities of hydrogen gas by synergism of hydrogen pressure and the catalyst (gravimetric hydrogen density per unit weight of NaBH4 and H2O including the Pt-LiCoO2 catalyst is 9.0 wt.%, volumetric hydrogen density per unit weight of NaBH4 and H2O including the Pt-LiCoO2 catalyst is 101 kg H-2/m(-3)). The hydrogen densities are high enough to reach the US Department of Energy (DOE) targets for use in a fuel cell vehicle (FCV) and also for other applications such as a fuel cell uninterrupted power supply (FCUPS). (C) 2004 Elsevier B.V. All rights reserved.