FIRST-PRINCIPLES STUDY OF Ti-CATALYZED HYDROGEN ADSORPTION ON LiB (001) SURFACE

Abstract

Ti-doped LiB (001) is a promising material for hydrogen storage. The adsorption of H-2 is greatly enhanced by doping Ti into LiB (001), change the electronic structures of the surface Li, B atoms. After H-2 is adsorbed on the surface, the E-ad of the (H-2)n@Ti/LiB (001) system is considered. It is around -0.22 eV/H-2 to -0.31 eV/H-2, which is close to the target specified by U. S. Department of Energy. The nature of the bonding between Ti and H-2 is due to the H 1s, Ti 4s and B 2s orbital hybridization. In addition, Ti 3d orbital is hybridized strongly with B-2p orbital, resulting in more stable Ti/LiB (001) system. These results are verified by the electron density distribution intuitively. It is found that the system can adsorb up to four H-2 at ambient temperature and pressure. Therefore, the Ti-doped LiB (001) would be a promising hydrogen storage material. Such optimal molecular hydrogen adsorption system makes H-2 adsorption feasible at ambient conditions, which is critical for practical applications.