BeS decorated with alkali-metal atom for outstanding and reversible hydrogen storage: A DFT study.

The potential for decorating single Li, Na, or K atoms onto BeS monolayers and their subsequent hydrogen storage performance were investigated using first-principle density functional theory (DFT) calculations. The single-atom Li, Na, or K exhibited strong adhesion to the BeS monolayer, with binding energies of −2.662 eV, −1.982 eV, or −1.669 eV, respectively. Each Li or Na atom on BeS demonstrated the ability to capture four H 2 molecules, while a single K atom could bind only three H 2 molecules. Notably, Li exhibited stronger binding with stored H 2 compared to Na or K. Moreover, by increasing the number of Li atoms on each side of the BeS monolayer to nine, the storage of H 2 molecules was improved to a total of 54, concomitant with an advantageous average adsorption energy of −0.236 eV. This enhancement resulted in a significant increase in the hydrogen storage capacity to 6.514 wt%. Molecular dynamics simulations indicated a desorption temperature of approximately 450 K, with the 18 Li atoms remaining strongly bonded to the BeS due to their high diffusion energy of 0.578 eV. Thus, the Li-decorated BeS monolayer emerges as a promising substrate for achieving exceptional and reversible hydrogen storage performance. • Alkali-metal atom (Li, Na, or K) could be well dispersed on the BeS monolayer. • Li atom shows a stronger adsorption strength to H 2 molecules than Na or K. • 18 Li atoms on BeS can capture 54H 2 with an ideal E adsav of −0.236 eV. • Li atoms remain dispersed on BeS even at desorption temperature of the 54H 2. • Li-decorated BeS demonstrates a high hydrogen storage capacity of 6.514 wt%. [ABSTRACT FROM AUTHOR]