The catalytic effect of Nb2O5 on the electrochemical hydrogenation of nanocrystalline magnesium

• DOI: 10.1016/j.jallcom.2005.06.063
• Publication Date: 2006-02-10T12:29:58Z
• Authors: D. Zander; L. Lyubenova; U. Köster; M. Dornheim; F. Aguey-Zinsou; T. Klassen
• Keywords: 02 engineering and technology; 0210 nano-technology; 7. Clean energy

Abstract Nanocrystalline Mg powder without and with 2 mol% Nb 2 O 5 catalyst was studied in a 6 M KOH electrolyte as electrode material for electrochemical hydrogen charging processes. Since the hydrogen overpotential of Mg, which is a measure of the hydrogen evolution at the electrode surface, was observed to be reduced by the addition of Nb 2 O 5 , it is assumed that the catalyst influences the electrode reactions. Considering this assumption hydrogenation was studied at different current densities. The storage capacity as well as the kinetic of Mg/Nb 2 O 5 electrodes increased significantly up to 1 wt.% H 2 at a charging time of 30 min with decreasing current density. The storage capacity of nanocrystalline Mg powder showed only minor changes to lower hydrogen contents with decreasing current density.