Computational Investigation of Adsorption of Molecular Hydrogen on Lithium-Doped Corannulene

Abstract

Density functional theory and classical molecular dynamics simulations are used to investigate the prospect of lithium-doped corannulene as adsorbent material for H₂ gas. Potential energy surface scans at the level of B3LYP/6-311G(d,p) show an enhanced interaction of molecular hydrogen with lithium-atom-doped corannulene complexes with respect to that found in undoped corannulene. MP2(FC)/6-31G(d,p) optimizations of 4H₂−(Li₂−C₂₀H₁₀) yield H₂ binding energies of −1.48 kcal/mol for the H₂−Li interaction and −0.92 kcal/mol for the H₂−C interaction, whereas values of −0.94 and −0.83 kcal/mol were reported (J. Phys. Chem. B2006, 110, 7688−7694) for physisorption of H₂ on the concave and the convex side of corannulene using MP2(full)/6-31G(d), respectively. Classical molecular dynamics simulations predict hydrogen uptakes in Li-doped corannulene assemblies that are significantly enhanced with respect to that found in undoped molecules, and the hydrogen uptake ability is dependent on the concentration of lithium dopant. For the Li₆−C₂₀H₁₀ complex, a hydrogen uptake of 4.58 wt % at 300 K and 230 bar is obtained when the adsorbent molecules are arranged in stack configurations separated by 6.5 Å, and with interlayer distances of 10 Å, hydrogen uptake reaches 6.5 wt % at 300 K and 215 bar.