A Ti-decorated boron monolayer: a promising material for hydrogen storage

A promising Ti-decorated boron monolayer (BM) system for hydrogen storage is proposed through the use of density functional theory. We find that the Ti decoration on the BM system is more stable, and the charge transfer between atoms will result in a more active system. The thermodynamic analysis showed that the doped Ti atoms reduced the thermodynamic stability of the BM sheets, but are suitable for a hydrogen storage system. One Ti atom-decorated BM can adsorb up to 5 H2 molecules, and the orbital interaction is mainly due to H 1s, Ti 3d and B1 2p orbital hybridization. The LST/QST calculation shows that cluster formation can be excluded due to the high energy barrier. Therefore, 16 Ti atoms can be decorated on the double faces of the H1t positions and the corresponding capacity of the system for H2 storage is calculated to be approximately 10.44 wt%. Our results suggest that the Ti-BM will be a promising material system for hydrogen storage.