With the idea to improve the efficiency of the electrolytic production of hydrogen by electrolysis, from water KOH solutions, the intermetallic Hf2Co was investigated as cathode. This cathode was used single or in combination with ionic activators, and compared with several intermetallics previously investigated: Hf2Fe, TiPt, and PtMo3. A comparison with conventional cathode, nickel, was also evaluated. An significant upgrade of the electrolytic efficiency using intermetallics was achieved in comparison with conventional cathode materials. The influence of ionic activators on the process efficiency was significant, too. The effects of those cathode materials on the electrolytic evolution of hydrogen were discussed in the context of transition metals features that issue from their electronic configuration. (c) 2005 Elsevier B.V. All rights reserved.