A DFT study of the hydrogen storage potentials and properties on Ca, Fe, and Ti deposited NaSi 20 fullerenes

Abstract

Abstract In this work, the hydrogen storage materials of Ca, Fe, and Ti deposited NaSi20 clusters have been investigated utilizing DFT methods (B3LYP and M06-2X) at the 6-311G(d, p) level. The orbital analysis and thermodynamic analysis were carried out and the adsorption capacity of H2 molecules by hydrogen storage materials are predicted. The results show that the encapsulated Na atoms in the Si20 cluster provide a relatively regular shape for the NaSi20 fullerene cluster. And Ca, Fe, and Ti atoms tend to bind with two adjacent Si atoms of NaSi20 cluster. The Ca@NaSi20, Fe@NaSi20, and Ti@NaSi20 can adsorb up to three, four, and six hydrogen molecules, respectively. The adsorption energy (Eads) per hydrogen molecule meets the United States Department of Energy (DOE) target for hydrogen storage materials for nH2-Ti@NaSi20 (n = 2–6) and nH2-Fe@NaSi20 (n = 1–4), implying that Fe and Ti deposited NaSi20 fullerene may be a potentially suitable material for hydrogen storage.