Density Functional Theory Study of Li-Functionalized Nanoporous R-Graphyne–Metal–Organic Frameworks for Reversible Hydrogen Storage

Hydrogen is the most convenient recourse to shift from fossil fuels to an efficient and sustainable source of energy in automobiles. Achieving a high hydrogen weight percentage while storing hydrogen is the prime challenge in using hydrogen fuel. In the current study, a nanoporous metal–organic framework of 2.069 nm pore size having R-graphyne as a linker (GR–MOF) is reported for the first time. Employing density functional theory, the hydrogen sorption characteristics of GR–MOF functionalized with Li and its mechanism are investigated. A Kubas-like mechanism is observed in the process of hydrogen adsorption with sorption energies in the 0.25–0.27 eV range, with the highest hydrogen weight percentage of 11.95%. It is observed during the van 't Hoff desorption and Born–Oppenheimer molecular dynamics study that GR–MOF reversibly stores hydrogen under operable thermodynamic conditions (100–300 K, 1–3 atm). GR–MOF stands out to be a prospective material for reversible hydrogen storage under the norms set by the Department of Energy, USA.