A novel, simple, convenient, and safe chemical process generates high purity hydrogen gas on demand from stable, aqueous solutions of sodium borohydride, NaBH4, and ruthenium-based (Ru), catalyst. When NaBH4 solution contacts Ru catalyst, it spontaneously hydrolyzes to form H-2 gas and sodium berate, a water-soluble, inert salt. When H-2 is no longer required, Ru catalyst is removed from the solution and H-2 generation stops. Since this H-2 generator is safer, has quicker response to H-2 demand, and is more efficient than commonly used H-2 generators, it is ideal for portable applications. (C) 2000 Elsevier Science S.A. All rights reserved.