A DFT STUDY OF Ti-DOPED Al NANOCLUSTERS FOR HYDROGEN BASED TRANSPORT VEHICLES

The present study aims to investigate the effect of Ti doping on stability and site preference in Ti doped Al₅clusters. Further, the interaction of the ground state TiAl₄ cluster with molecular hydrogen has also been investigated. To predict the Ti-doped structures and the properties of Ti-Al nano-clusters, Density Functional Theory (DFT) is employed as implemented in the Vienna abinitio simulation package (VASP) using general gradient approximations (GGA) without imposing any symmetry constraints. The study shows that the Al₅ cluster exists in two stable ground state geometric configurations with planar W shape and square pyramidal C₂V symmetry. The Ti-doped cluster is more stable than the bare Al₅ nano-clusters. The Ti atom prefers the site which has maximum Ti-Al bonds. The Ti-Al bond length is small as compared to the Al-Al bond length resulting in slight geometric distortions in the Al clusters. Hydrogen interaction study shows that hydrogen adsorption energy on the TiAl₄ cluster is as low as -0.026 eV/ atom. Thus, Ti-Al nano-clusters are a stable, efficient, and economical candidate for hydrogen storage materials.