A DFT analysis unravelling hydrogen sorption pathways in Laves phase Cu2Cd

Abstract

A comprehensive study to establish sorption pathways for molecular and atomic hydrogen in Cu2Cd Laves phase by means of density functional theory calculations is reported. The surface energy of Cu2Cd was calculated exposing the (0001) surface with two different planes, one being Cu terminated while the other being Cu-Cd terminated. Both were discerned to have comparable surface energies. Adsorption sites for the relevant molecular and atomic hydrogen were identified on both the planes and the associated energetics were determined. Adsorption of atomic hydrogen was found to be energetically favoured when compared to the molecular adsorption of hydrogen. Diffusion pathways for atomic hydrogen from the surface to the bulk were investigated. The study provides detailed insights into the identification and energetics of the surface adsorption of hydrogen, and its diffusion to the subsurface sites, thus unravelling the sorption pathways in Cu2Cd Laves phase for potential hydridic storage of hydrogen.