H/H2在焊接型(5,5)碳纳米关内外的结合能

In this work, the binding energies of H/H2 both inside and outside the (5, 5) single-walled carbon nanotube (SWCNT) and welding carbon nanotube T (5, 5) are investigated by using density functional theory (DFT). The effect of the orientations and locations of hydrogen atom and molecule on the binding energy are discussed. During the calculating process, the H atom upon a carbon atom (top) has the largest binding energy, while the H2 which is placed perpendicular to the wall upon the center of a hexagon of carbon atoms inside the carbon nanotube is predicted to be the most stable state. The binding energies of H atom inside the SWCNT (5, 5) are in the range of -0.35 - -0.69eV, while the corresponding values of the T (5, 5) are in the range of -0.95 - -1.27eV. The binding energies of H2 molecule inside the SWCNT (5, 5) are in the range of -0.15 - -0.17eV, while the corresponding results for the T (5, 5) are in the range of -0.31 - -0.38eV. It can be seen that the binding energy of H/H2 in the T (5, 5) is obviously larger than that in the SWCNT (5, 5). This result means that the welding structure is suitable for hydrogen storage.