Yttrium dispersion on capped carbon nanotube: Promising materials for hydrogen storage applications

Based on the density functional theory calculations, we predict that the Yttrium-dispersed capped-carbon nanotubes (CCNY) can serve as a high-capacity hydrogen storage material. The interaction of H2 molecules with the CCNT can be significantly enhanced upon decoration by Y atoms. The H2 molecules binding to the Y-CCNT system is similar to the Y-C60 system with a maximum of six H2 molecules per Y atom and an average binding energy of −0.48 eV, which is suitable for reversible hydrogen storage at ambient conditions. With six Y atoms located, the gravimetric density of the cap is found to be 7.51 wt%, thus exceeding the 6.5 wt% target of the U.S. Department of Energy.