Hydrogen storage on scandium-coated toroidal carbon nanostructure C 120 modeled with density functional theory

Abstract

Ab initio density functional calculations were performed on a toroidal carbon C120 nanostructure doped from one to ten Sc atoms bonded to its outer surface. These calculations are based on DFT with the generalized gradient approximation PW91 (Perdew and Wang) as implemented in the Materials Studio v.4.3 code. The Dmol3 module was used to calculate, among others, total energies, charge density, HOMO-LUMO and Mulliken population analysis. On the basis of these results, it is possible to propose that a single Sc atom is able to adsorb up to 6 H2 molecules. Therefore the study was extended for a system with 10 Sc atoms, which can adsorb up to 60 H2 molecules. This leads to 6.01 wt %, which fulfils the current requirement (6 wt %, at 2010, specified by US Department of Energy (DOE)). Accordingly, the scandium-coated toroidal carbon C120 nanostructure is a good candidate for H2 storage with moderate adsorption energy.