Synthesis of ultrafine titanium aluminide powders and their catalytic enhancement in dehydrogenation kinetics of NaAlH4

Titanium aluminide powders with various sizes have been synthesized using four different mechanochemical reactions. While the reaction between TiCl3, AlCl3 and Mg produces TiAl3 nanopowder with a primary particle size of about 50 nm, the use of LiH instead of Mg results in the formation of Ti2Al5. These titanium aluminide powders reveal a considerable catalytic effect on dehydrogenation of NaAlH4. It is also found that the catalytic effect is particle-size dependent.