Synergistic effect of Li–Ti and K–Ti co-doping on the dehydrogenation properties of NaAlH4: an ab initio study
Abstract
The synergistic effect of Li–Ti and K–Ti dopants on the energy, structure and electronic properties of NaAlH4 has been investigated using density functional theory and ab initio molecular dynamics. Pair distribution functional analyses show that the substitution of NaAlH4 by Li2Ti and K2Ti favor not only the release of H2 but also the reductions in the barrier energies of (AlH4)− units. Density of states analyses suggest that the weakening of Al–H bonds in Li2Ti- and K2Ti-doped NaAlH4 is attributed to the formation of Ti–Al and Ti–H phases. Bader atomic charges analyses imply that the strong interaction of Li–Al prevent the further formation of Ti–Al clusters. The results of H removal energies analyses reveal that both Li2Ti and K2Ti are favorable catalysts for NaAlH4. Thus, that a Li2Ti dopant, with lighter weight than K2Ti, can be applied as a favorable catalyst for NaAlH4 has been given for the first time.