Density functional theory study of Li-Functionalized nanoporous R‑Graphyne−Metal−Organic frameworks for reversible hydrogen storage

Abstract

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.