Colloidal Suspensions of Highly Reduced Graphene Oxide in a Wide Variety of Organic Solvents

Abstract

We report that homogeneous colloidal suspensions of chemically modified graphene sheets were readily produced in a wide variety of organic solvent systems. Two different sets of solubility parameters are used to rationalize when stable colloidal suspensions of graphene oxide sheets and, separately, of reduced graphene oxide sheets in a given solvent type are possible and when they are not. As an example of the utility of such colloidal suspensions, "paperlike" materials generated by very simple filtration of the reduced graphene oxide sheets had electrical conductivity values as high as 16,000 S/m.

A low-temperature method to produce highly reduced graphene oxide

“…3d, recorded using 514 nm laser irradiations. The I D /I G ratio of RGO Na-NH 3 did increase notably, indicating that the reduction process altered the structure of GO 32,33 . It is particularly important to note that the intensity of the two-dimensional peak of RGO Na-NH3 is much stronger than that of RGO NH2NH2 , suggesting a better graphitization in RGO Na-NH 3 18 .…”

“…Although a prominent D peak is typically an indication of disorder in the Raman of peeled graphene, our observations are consistent with previous reports of RGO materials 28 . A greater ratio of the Raman D/G intensity of the RGO Na-NH 3 films compared with the GO film indicates an increase in the number of smaller sp 2 domains 33,34 .…”

Chemical structures of hydrazine-treated graphene oxide and generation of aromatic nitrogen doping

“…For the last half decade, among several chemical reductants 4,5 , hydrazine has been the most commonly used reductant due to its ease of use (for example, via a one-pot synthesis in either liquid or gas phase) and its ability to achieve a high degree of reduction of graphene oxide without the need for further treatment 3,[6][7][8] . Hydrazine-treated graphene oxide (chemically reduced graphene oxide, 'CReGO') 3 is one of the most promising graphene-based materials for several applications, such as polymer composites, ultracapacitors, rechargeable batteries, chemical/biosensors and thin films [9][10][11][12][13][14] .…”

Processing and characterisation of Mo6S2I8nanowires

“…[16][17][18] It considers the energy changes that occur upon solvation. The free energy of mixing is given by the well-known formula DG mix = DH mix À TDS mix (6) and must be negative for solvation to occur, giving…”

“…16 For solvation to be possible at modest temperatures it is therefore necessary to minimise the enthalpy of mixing. Consideration of the energy changes that occur when NWs are brought from infinity into voids in the solvent gives the following expression for the enthalpy of mixing 16…”