Nickel doped defective h-BN nanosheets and their potential application on hydrogen storage were explored by density functional theory (DFT) calculation. Three types of defective h-BN (SW defect, V-B and V-N substrates) were modeled. In comparison with the SW defect, the B or N vacancy can improve the interaction between Ni atom and h-BN nanosheet strikingly. Furthermore, the Ni-doped SW defect sheet shows chemisorption on H-2 molecules, and the H-H bond is partially dissociated. While on the VB sheet, Ni adatom interacts with H-2 in the range of physisorption. However, the Ni-functionalized VN sheet exhibits a desirable adsorption on H-2, and the corresponding energy varies from -0.40 to -0.51 eV, which is favorable for H-2 adsorption and release at ambient conditions. As a result, the VN substrate is expected to a desirable support for H-2 storage. Our work provides an insight into H-2 storage on Nifunctionalized defective h-BN monolayer. (C) 2018 Elsevier B.V. All rights reserved.