▎ 摘　　要

Ionic liquids (ILs) are promising novel solvents for energy harvesting and understanding the graphene/ILs interface structural characteristics is required. In this study, we calculate the vibrational spectrum (VS) of 1-ethyl-3-methylimidazolium tetrafluoroborate ([Emim][BF4]) pair on graphene surface in the range from 10 to 3500 cm(-1) and systemically investigate the influence of the graphene on the VS of [Emim][BF4] using density functional theory. The results show 24 vibrational bands (VBs) with obvious shifting. The VBs at 3170.26 and 3033.51 cm(-1) show a redshift of 59.46 and 14.95 cm(-1) respectively which was mainly caused by the enhanced hydrogen bond strength of C2-H center dot center dot center dot F and F atoms with the C-H on the ethyl chain. The VBs at 101.49 and 1417.43 cm(-1) show a blueshift of 62.43 and 23.86 cm(-1) due to the enhancement of induction effect of [Emim][BF4]on graphene surface (from -44.68 to -45.42 kJ mol(-1)). The VB at 86.91 cm(-1) shows a redshift of 59.43 cm(-1) which can be ascribed to the reduction of the whole interaction energy between the cation and anion of [Emim][BF4] on graphene surface (from -367.06 to -356.06 kJ . mol(-1)). Overall, these shifts of the VS are mainly attributed to the attraction between graphene and anion [BF4](-), which is dominated by the induction and dispersion interaction accounting for 63.43% and 34.37% of the attraction interaction respectively. Due to this attraction, the anion [BF4](-) move doser to the surface of graphene. (C) 2020 Elsevier B.V. All rights reserved.