Nanocrystalline MgH2/MexOy composite powders were produced by high energy b
all milling (MexOy = ScO3, TiO2, V2O5, Cr2O3, Mn2O3, Fe3O4, CuO, Al2O3, SiO
2), The hydrogen absorption and desorption kinetics were determined in view
of a technical application. The addition of selected oxides lead to an eno
rmous catalytic acceleration of hydrogen sorption compared to pure nanocrys
talline hydrides. In absorption, the catalytic effect of TiO2, V2O5, Cr2O3,
Mn2O3, Fe3O4, and CuO is comparable. Concerning desorption, the composite
material containing Fe3O4 shows the fastest kinetics followed by V2O5, Mn2O
3, Cr2O3 and TiO2. Only 0.2 mol% of the catalysts is sufficient to provide
a fast sorption kinetics. Additionally, Mg absorbs hydrogen already at room
temperature by the use of metal oxides as catalysts. Furthermore, it is de
monstrated for the first time that MgH2/MexOy-powders release hydrogen at 2
00 degreesC.