First-Principles Study of Titanium-Doped B₇ Cluster for High Capacity Hydrogen Storage

The geometrical structure, stability, electronic properties, and hydrogen storage capabilities of a titanium-doped B₇ cluster was calculated using density functional theory computations. The results show that the TiB₇ cluster is predicted to be stable under near-ambient conditions based on an ab initio molecular dynamic simulation. The transition state analysis found that the H₂ molecule can dissociate on the TIB₇ cluster surface to form a hydride cluster. The Ti atom within the TiB₇ cluster demonstrates an impressive capacity to adsorb up to five H₂ molecules, achieving a peak hydrogen storage mass fraction of 7.5%. It is worth noting that the average adsorption energy of H₂ molecules is 0.27-0.32 eV, which shows that these configurations are suited for reversible hydrogen storage under mild temperature and pressure regimes. In addition, calculations found that both polarization and hybridization mechanisms play pivotal roles in facilitating the adsorption of H₂ molecules onto the TiB₇ cluster. Our research results show that the TiB₇ cluster has potential for hydrogen storage applications under near-ambient conditions.