No abstract

Mechanical processing of polycrystalline LiAlH in the presence of titanium-and iron-based catalysts induces the transformation of 4 LiAlH into Li AlH , Al and H at room temperature. Several catalysts were tested and it was established that their activity gradually 4 3 6 2 decreases from TiCl to Fe in the series TiCl .Al Ti4Al Fe Ti .Al Fe.Fe. The high catalytic activity of TiCl has been attributed 4 4 3 2 2 3 8 3 4 to microcrystalline intermetallic Al Ti, which rapidly forms in situ from TiCl and LiAlH during mechanical processing and then acts as 3 4 4 a heterogeneous dehydrogenation catalyst.

Mechanochemical processing of polycrystalline LiAlH revealed good stability of this complex aluminohydride during high-energy 4 ball-milling in a helium atmosphere for up to 35 h. The decomposition of lithium aluminohydride into Li AlH , Al and H is observed 3 6 2 during prolonged mechanochemical treatment for up to 110 h and is most likely associated with the catalytic effect of a vial material, iron, which is introduced into the hydride as a contaminant during mechanical treatment.