The effect of creating a vacancy along with the inducing electrical charge on the interaction between water molecule (H2O) with boron nitride nanosheet in either pristine (BNNS) or vacancy defected state (VD-BNNS) has been studied using the density functional theory (DFT). It was found that H2O is molecularly physisorbed on the vacancy-free surface of VD-BNNS as well as the surface of BNNS. In contrast, within the vacancy, the H2O is dissociated upon a mechanism that depends on the amount of induced charge on the nanosheet. Structural and electronic properties including the formation Gibbs free energy of nanosheet, Natural bond orbital (NBO) electrostatic charges, electron density distribution, energy gap, chemical potential, total chemical hardness, and electrophilicity index are calculated and used to understand the factors affecting the adsorption of H2O. The energy profile and the mechanism of H2O dissociation by VD-BNNS were also studied and the kinetical parameters of the reaction were calculated.
