Mg-Based Hydrogen Storage Materials with Improved Hydrogen Sorption

抄録

Nanocrystalline MgH₂/Me_xO_y composite powders were produced by high energy ball milling (Me_xO_y=Sc₂O₃, TiO₂, V₂O₅, Cr₂O₃, Mn₂O₃, Fe₃O₄, CuO, Al₂O₃, SiO₂). The hydrogen absorption and desorption kinetics were determined in view of a technical application. The addition of selected oxides lead to an enormous catalytic acceleration of hydrogen sorption compared to pure nanocrystalline 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, Mn₂O₃, 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 demonstrated for the first time that MgH₂/Me_xO_y-powders release hydrogen at 200°C.