Abstract

The hydrogen storage properties of Ti-doped B-n (n=3-12) clusters are investigated by using the "diatomic deposition method" with further evaluation by density functional theory computations. The results show that TiBn (n=7-9) clusters possess the ability to storage up to four H-2 molecules, reaching a mass fraction of 6.12%. Further, the hydrogen release temperature is analyzed by molecular dynamics simulations with a variable temperature. It turns out that the TiB7 and TiB9 clusters release the H-2 molecules at T less than or similar to 700 K, while TiB8 requires higher temperature due to stronger interactions with the H-2 molecules, confirmed by the electronic density of states. The size-dependent properties and odd-even nuclearity on the clusters can be useful for applications with controlled temperature. These results serve for further design of novel materials with reversible and controlled hydrogen storage properties based on TiB7/TiB9 motifs. Additionally, new lower-energy isomers for TiB4 and TiB9 clusters were found within the accuracy of the all-electron triple-zeta Slater [slater type orbital (STO)-Triple-zeta basis set(TZP)] basis set.