I was perfoming the modified Hummers method and when I added the peroxide the solution went from brown to transparent yellow. After centrifugation, the graphene oxide(?) At the bottom is transparent! What could have happened? Is that still graphene oxide? Thanks!
Most likely, still GO, but oxidized too much: sheets are small (and therefore soluble), and aromatic backbone mostly lost. You might wish to check with TEM and AFM.
Hi Ana
Modifications in development of graphene oxide synthetic
routes
S. Shamaila,* a A. K. L. Sajjadb and I. Anuma
( conversion of graphite into graphitic oxide yields black suspension of graphite oxide in
large volume of water. But the suspension becomes dark green at carbon to oxygen ratios of
about 3.0 to 3.4. The colour of suspension is light green for the carbon to oxygen ratio of
about 2.8 to 3.0. The colour becomes yellowish green by further decrease in carbon to
oxygen ratio. The bright yellow colour can be achieved at the lowest carbon to oxygen ratio
of about 2.05 to 2.4. Different oxidative treatments yield variety of products having)
GO BRIGHT YELLOW COLOUR
Measurements must be made to confirm that they are XRD ,UV,TEM
I wish you success.
I've seen something similar when a large excess of oxidising agent (i.e permanganate) is used and/or the reaction has been left for a long time which results in the complete decomposition of GO into small highly oxidised organic molecules. Although I don't think in your case it has gone to this extent.
How did you make GO?
I used 18g of permanganate. But I started from sub-bituminous coal. The experiment lasted for about 12 hours.
It would be interesting to see what type of GO you have made, i.e. quantum dots, nanoflakes or just highly oxidised large GO sheets. Would you be able to characterise the GO using an imaging technique such as AFM? Or are you after a particular type of GO?
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