First-principles study of interaction between H2 molecules and BN nanotubes with BN divacancies

The interaction between H(2) molecules and boron nitride (BN) single-walled nanotubes with BN divacancies is investigated with density-functional theory. Our calculations reveal that H(2) molecules adsorb physically outside defective BN nanotubes, and cannot enter into BN nanotubes through bare BN divacancies because the energy barrier is as high as 4.62 eV. After the defects are saturated by hydrogen atoms, the physisorption behavior of H(2) molecules is not changed, but the energy barrier of H(2) molecules entering into BN nanotubes through the defects is reduced to 0.58 eV. This phenomenon is ascribed to hydrogen saturation induced reduction of electrostatic potential around the defects.