Chemistry Reference
In-Depth Information
(polyoxyethylene (40) nonylphenylether, IGP), sodium dodecylsulfate
(SDS) and cetyltrimethylammoniumbromide (CTAB) gives water-
soluble graphene. Figure 6(f) shows and IGP photographs of water-
soluble graphene obtained with CTAB, SDS [47]. Water-soluble
graphene can also be prepared by PEGylation method in which, acidified
graphene is treated with excess of polyethylene glycol (PEG) and conc.
HCl under solvothermal conditions [35].
4. SURFACE PROPERTIES
Single-layer graphene is theoretically predicted to have large surface
area of 2600 m
2
/g [49]. We have measured the surface properties
of few-layer graphene samples prepared by different methods. The
BET surface area of these samples are found to be in the range of
270-1550 m
2
/g, some of them approaching the value of single-layer
graphene (Fig. 7(a)) [50].
Fig. 7. (a) Nitrogen adsorption and desorption isotherms of graphene at 1 atm and 77 K
and (b) Adsorption and desorption isotherms of CO
2
at 1 atm and 195 K. Inset in
Fig. 7(a) shows the linear relation between the BET surface area and the weight
percentage of hydrogen uptake at 1 atm and 77 K (From reference 50).
The surface area varies as EG > DG > EG-H > HG. We considered
that these high surface area samples might enable storage of hydrogen.
Hydrogen storage reaches 3 wt% at 100 bar and 300 K and the uptake
