Reduced Graphene Oxide Powders

At Ossila, we have found that the most stable solutions can be produced using the following recipe:

• Weigh out desired amount of material, this can go up to around 0.1 mg.ml^-1.
• Add 3:2 ratio of isopropyl alcohol to ethylene glycol.
• Shake vigorously to break up material.
• For chemically-reduced graphene oxide, use a mechanical agitator instead (as sonication may damage the flakes).
• For thermally-reduced graphene oxide, a prolonged treatment in an ultrasonic bath can help to break up and disperse the material.

What is Reduced Graphene Oxide?

When produced, graphene oxide typically has a wide array of different oxygen functional groups present: 1,2-epoxide and alcohol groups on the basal planes, and carboxyl and ketone groups at the edges. Graphene oxide can be readily dispersed in a range of solvents at high concentration, either for additive processing with other materials or for the processing of thick layers. However, graphene oxide does not have the same exceptional physical and electronic properties that make graphene unique. Regardless, graphene oxide can be reduced fully or partially to produce a graphene-like structure by removing the oxygen functional groups present.

Reduced graphene oxide can be tuned by varying the degree of reduction, either by using thermal reduction or various forms of chemical reduction. Thermal reduction typically produces a higher degree of reduction than chemical processes, giving higher electrical conductivity. However, due to the high temperatures involved, this can lead to damage of the individual flakes -- either through the breaking of flakes, or through the introduction of defects within the structure. On the other hand, chemical reduction allows for the retention of flake sizes of the graphene oxide used, as well as a lower defects density per flake.

4. Atomic Structure of Reduced Graphene Oxide, C. Gómez-Navarro et al., Nano Lett., 10 (4), 1144–1148 (2010); DOI: 10.1021/nl9031617.
5. Determination of the Local Chemical Structure of Graphene Oxide and Reduced Graphene Oxide, K. Erickson et al., Adv. Mater., 22, 4467–4472 (2010); DOI: 10.1002/adma.201000732.
6. Graphene Oxide, Highly Reduced Graphene Oxide, and Graphene: Versatile Building Blocks for Carbon-Based Materials, O. C. Compton et al., small, 6 (6), 711–723 (2010); DOI: 10.1002/smll.200901934.
7. Reduced graphene oxide/carbon nanotube hybrid film as high performance negative electrode for supercapacitor, X. Cui et al., Electrochimica Acta 169, 342–350 (2015); doi:10.1016/j.electacta.2015.04.074.
8. Few-Layered SnS2 on Few-Layered Reduced Graphene Oxide as Na-Ion Battery Anode with Ultralong Cycle Life and Superior Rate Capability, Y. Zhang et al., Adv. Funct. Mater., 25, 481–489 (2015); DOI: 10.1002/adfm.201402833.
9. Reduced Graphene Oxide Micromesh Electrodes for Large Area, Flexible, Organic Photovoltaic Devices, D. Konios et al., Adv. Funct. Mater., 25, 2213–2221 (2015); DOI: 10.1002/adfm.201404046.
10. Thermally reduced graphene oxide films as flexible lateral heat spreaders, N-J. Song et al., J. Mater. Chem. A, 2, 16563 (2014); DOI: 10.1039/c4ta02693d.
11. Supercapacitor performances of thermally reduced graphene oxide, B. Zhao et al., J. Power Sources, 198, 423-427 (2012); doi:10.1016/j.jpowsour.2011.09.074.
12. Controlled ripple texturing of suspended graphene and ultrathin graphite membranes, W. Bao et al., Nanotechnol. 4, 562–566 (2009); DOI: 10.1038/nnano.2009.191.
13. Thermally reduced graphene oxide-coated fabrics for flexible supercapacitors and self-powered systems, A. Ramadoss et al., Nano Energy, 15, 587-597 (2015); doi:10.1016/j.nanoen.2015.05.009.
14. Characteristics of thermally reduced graphene oxide and applied for dye-sensitized solar cell counter electrode, C-Y. Ho et al., Appl. Surf. Sci., 357, 147-154 (2015); DOI: 10.1016/j.apsusc.2015.09.016.