The search for optimum host-guest interactions: Atomic hydrogen storage properties of the novel ternary ordered intermetallic compound Cu3ZnSb: A DFT study.

Ternary Cu 3 ZnSb adopts the tetrahedral space group P 4/ nmm (129), with 10 atoms in the unit cell, distributed over four crystallographic positions in a perfectly ordered manner. It possesses two perfect tetrahedral interstitial positions, namely Cu 3 Sb and Cu 2 Zn 2. The possible hydrogen storage properties in these two possible sites are explored by the aid of first-principles density functional theory calculations. The Cu-richer Cu 3 Sb site is energetically more favourable position for hydrogen atom, over the other one. The maximum possible H-uptake capacity would be within the range of ∼4 H per formula unit. The electronic structure modification, host-guest interactions, and electronic redistribution after hydrogen incorporation are explored from fundamental perspectives analyzing the density of states, crystal orbital Hamilton population, crystal orbital bond index, and Mulliken population calculations. [Display omitted] • The atomic hydrogen absorption properties of Cu 3 ZnSb have been explored by first-principles calculations. • The Cu-richer Cu 3 Sb site is energetically more favourable than the Cu 2 Zn 2 -site. • The electronic structure modification up on bulk hydrogenation was explored by comparing the density of states. • COHP and COBI calculations extract the detailed information of the host(H)-guest (IMC) interactions. • Mulliken population analysis confirms the electronic redistribution after hydrogenation. [ABSTRACT FROM AUTHOR]