Influence of noble metals on the electronic and optical properties of LiH hydride: First-principles calculations

Abstract

Lithium hydride (LiH) has attracted attention because of its high density hydrogen storage energy. However, the poor dehydrogenation properties cannot be used as an effective hydrogen storage material. In this paper, we apply the first-principles calculations to study the influence of noble metals on the electronic and optical properties of LiH hydride. Here, five noble metals TM(TM = Ag, Au, Pd, Pt and Ru) are considered. The calculated result shows that the noble metals are thermodynamic stability in LiH hydride. In particular, it is found that only the Pt-doped LiH is a dynamical stability compared to the other noble metals doping. Here, the calculated band gap of the pure LiH is 3.002 eV. Interestingly, these noble metals are beneficial to improve the electronic transfer (near Fermi level) of LiH because the introduction of noble metal induces the H-1s state to the Fermi level, making the band gap of the noble metal doped LiH disappear. In addition, we study the influence of noble metal Pt on the optical properties of LiH. It is found that the Pt doping can enhance the optical activity of LiH for visible light and infrared light, presumably caused by the addition of d state.