▎ 摘　　要

Graphene has potential applications in many fields. In particular, two-dimensional graphene nanochannels assembled from graphene sheets can be used for filtration and separation. In this work, molecular dynamics simulations were performed to investigate the microscopic structural and dynamical properties of water molecules confined in pristine and hydroxyl-modified graphene slit pores with widths of 0.6-1.5 nm. The simulation results indicate that water molecules have layered structure distributions within the graphene nanoscale channels. The special ordered ring structure can be formed for water confined in the subnanometer pores (0.6- 0.8 nm). Graphene surfaces are able to induce distinctive molecular interfacial orientations of water molecules. In the graphene slits, the diffusion of water molecules was slower than that in bulk water, and the hydroxyl-modified graphene pores could lead to more reduced water diffusion ability. For the hydroxyl- modified graphene pores, water molecules spontaneously permeated into the 0.6 nm slit pore. According to the simulation results, the dynamic behavior of confined water is associated with the ordered water structures confined within the graphene-based nanochannels. These simulation results will be helpful in understanding the penetration mechanism of water molecules through graphene nanochannels, and will provide a guide for designing graphene-based membrane structures.