First Principles Study of Hydrogen Desorption from the NaAlH4 Surface Doped by Ti Clusters

On the basis of density functional calculations, we show that a Ti-4 cluster adsorbed at the (101) surface of NaAlH4 is able to catalyze both the release of H-2 and the formation of A1H(5)(2-) groups which have been previously proposed to be the mobile species leading to the formation of the Na3AlH6 product during the dehydrogenation of Na alanate.