Electronic and dehydrogenation properties of TiB2 cluster-doped NaAlH4 (101) surface: A first-principle approach

The crystal structures, electronic and dehydrogenation properties of TiB2 cluster-doped NaAlH4 (101) surface have been investigated by the first-principles density functional theory method. In the TiB2 cluster-doped NaAlH4 (101) surface, a Ti-centered TiB2–Al2H8–AlH5–AlH3 complex is observed, and the AlH3 and (AlH5)2− units in the TiB2–Al2H8–AlH5–AlH3 favor the first-step decomposition reaction of NaAlH4. The calculated electronic properties show that B–Ti bonds are stronger than B–Al and Ti–H bonds, which demonstrates that TiB2 does not change its configuration in catalyzing the decomposition reaction of NaAlH4. The results of hydrogen desorption energies imply that the import of TiB2 makes the strength of Al–H bonds decreases. Therefore, the removal of H atoms, especially the removal of H atoms in the Ti–H–Al bonds is easier in the TiB2 cluster-doped NaAlH4 than in pure NaAlH4.