Catalytic effects of pseudo AB2 phases on hydrogen sorption

The compound GdNi4Mg in its amorphous and crystalline state has been investigated as catalyst for hydrogen sorption of magnesium. Addition of only 0.3 at.% of catalyst by ball milling resulted in an important improvement of hydrogen sorption kinetics. Optimum milling time has been found to be 5 h. The amorphous and crystalline GdNi4Mg compounds give almost identical kinetics. Both absorption and desorption have been improved and the kinetics obtained are almost the same as other metal catalysts. No evidences of decomposition during ball milling or hydrogenation have been found so that it should be concluded that the intermetallic itself acts as a catalyst.