Fig. 2. Structural properties of graphene oxide.

Histograms of the C–C distance d_C–C (a), the $\widehat{\mathrm{CCC}}$ angle (b), and the $\widehat{\mathrm{COC}}$ angle (c) for semiordered (black) and random (red) graphene oxide models. Blue dashed lines correspond to the values in reference systems: d_C–C = 1.42 Å in graphene, ${\widehat{\mathrm{CCC}}}_{s{p}^3}=109.28^{\circ }$, ${\widehat{\mathrm{CCC}}}_{s{p}^2}=120^{\circ }$, and $\widehat{\mathrm{COC}}=60^{\circ }$ for epoxide. d Histogram of the $\widehat{\mathrm{COH}}$ angle for the GO in vacuum (dashed lines) and GO solvated in water (solid lines). e Snapshots of the different H bonds (visualized as blue dashed lines) types classified in Table 3. The atoms of each type of chemical function (hydroxyl group or epoxide) involved in the H bonds between the surface and H₂O are highlighted in orange.