Scandium/Lithium-Functionalized c-IRMOF-10 as a Highly Efficient and Fast-Kinetic Hydrogen-Storage Medium: An Ab Initio DFT and AIMD Study

Abstract

Isoreticular metal–organic framework-10 (IRMOF-10) beryllium-based nanoporous materials are receiving great interest as H2-storage media due to the low atomic mass of beryllium and the stability of decorating light metals (Li, Sc) on the organic linker by the hybridization of orbitals. In this computational theory, we first demonstrated the energetic stability of connector-IRMOF-10 (c-IRMOF-10) through density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations. Our results revealed that the Li and Sc atoms prefer to adsorb at the organic linker with binding energies of −306.82 and −411.02 kJ/mol, respectively. In the hydrogenation process, 8Li@c-IRMOF-10 and 8Sc@c-IRMOF-10 adsorbed 24 H2 and 28 H2 molecules, respectively, having average adsorption energies within the desired range for effective storage/release cycles. The maximum gravimetric density is found to be 8.27 and 6.78 wt % for Li- and Sc-decorated c-IRMOF-10, respectively. It is observed during the van‘t Hoff desorption and AIMD calculation study that Li/Sc@c-IRMOF-10 reversibly stores hydrogen under ambient conditions. H2 migration on the surface of Li/Sc@c-IRMOF-10 is confirmed to be fast along the ring center, owing to a low activation energy of ∼1.59/2.18 kJ/mol. We believe that our findings on functionalization/substitution methods are important for achieving the optimal H2-storage properties of c-IRMOF-10.