fig6

Figure 6. Regulating the size of nanochannels. (A) Physical confinement. (B) The stable, optimized geometries of Na+-(H2O)6@GO clusters from density functional theory computation[101]. Copyright 2017, Springer Nature. (C) The fabrication procedure of free-standing rGO membranes using reduction control[104]. Copyright 2015, John Wiley & Sons, Inc. (D) Original GO membrane (left) and the composite GO-framework prepared by p-phenylenediamine cross-linking GO membrane (right)[105]. Copyright 2014, American Chemical Society. (E) Graphene/carbon nanotube composite membranes are prepared by assembling refluxed GO (rGO) and multi-walled carbon nanotubes[120]. Copyright 2015, American Chemical Society.