Computational evaluation of scandium decorated boron oxide monolayer as reversible hydrogen storage medium

Two-dimensional (2D) materials with a high surface-to-volume ratio and excellent electronic properties have been extensively used as hydrogen (H₂) storage mediums. In this study, the first-principles calculations have been implemented to explore the structural, electronic and H₂ storage performance of recently synthesized boron monoxide (BO) monolayer decorated with the scandium (Sc) dopants. It is found that doping with three Sc atoms, resulting in the formation of 3Sc@BO material, changes the electronic properties of BO from semiconducting to conducting. The Sc dopants are bonded with the BO in the form of Sc–O bonds with significantly strong binding energies of −4.628, −4.708 and −4.323 eV/Sc, for Sc@BO, 2Sc@BO, and 3Sc@BO, respectively. Thermal stability of the 3Sc@BO system is verified through ab initio molecular dynamics (AIMD) simulations. The H₂ molecules adsorbed on 3Sc@BO are polarized and exhibit the obvious hybridization between H₂ and Sc. Under maximum hydrogenation, the 3Sc@BO could adsorb to a maximum of 19H₂ molecules, resulting in a high storage capacity of 10.96 wt%, and the average adsorption energy is −0.35 eV/H₂. The adsorption of H₂ on 3Sc@BO is elaborated as a synergistic collaborative amalgamation of physical and chemical adsorption mechanisms. Furthermore, relative energy analysis indicates that H₂ molecules remain adsorbed on 3Sc@BO at 298.15 K and moderate pressures, and the desorption occurs at temperatures above 319 K. Our findings reveal the potential of 3Sc@BO as a high-capacity H₂ storage material.