▎ 摘　　要

Using density functional theory, we investigated the interaction of an NH3 molecule with a pristine and antisite defected BN sheet (g-BN) in terms of energetic, geometric, and electronic properties. The adsorption energy of NH3 on defected g-BN was calculated to be in the range of -0.70 to -2.46 eV, which is considerably more negative than that on the pristine sheet. It was found that the adsorption of NH3 adsorption on the defected sheet may cause the release of an H-2 molecule. The electronic properties of the defected BN sheet were significantly changed after the adsorption process so that its HOMO/LUMO energy gap was changed from 3.31 to 3.60-4.97 eV. Moreover, the Fermi level of the defected sheet shifts to higher energies after the interaction, which results in reduced potential barrier of the electron emission for the sheet surface, enhancing the field emission because of the decreased work function.