Anionic LaH - 8: A Nanocluster-Based Hydrogen Storage Material

Abstract

The geometric structures of anionic LaH^-_n (n=2-20) clusters are predicted by CALYPSO cluster structural search method and first-principles calculations. The low-lying isomers for each size of LaH^-_n (n=2-20) clusters are further reoptimized at B3LYP level by setting all-electron 6-311G++(d, p) basis set for H atoms and SDD basis set for La atom, respectively. The photoelectron spectroscopy (PES) of the ground-state structures are simulated by time-dependent DFT (TD-DFT) method. It is found that the anionic LaH^-₈ cluster with D_2d symmetry is the most stable structure and its hydrogen storage capacity arrives at 5.4 wt%. The stability of anionic LaH^-₈ cluster is mainly affected by the strong interaction between H 1s orbital and La 5d orbital. The present results provide insights into the further exploration and discovery of novel rare-earth based hydrogen storage nanomaterials.