I have synthesized graphite oxide using Hummers method, but sometimes the color of the product is thick brown and sometimes brownish black. After dispersion in water, both look like same (brown solution), so how can I identify the good one?
The easier and quickest way to check the quality of graphite oxide is by XRay analysis. The peak of graphite at around 26 deg should completly disappear. You would instead have a peak at lower angles (around 13-14 deg) indicating the increase in interlamelar distance.
First question: are the reaction conditions same.. and the starting material, graphite is of the same particle size?? Smaller PSD graphite tends to get oxidized more easily.
Secondly, the color of GO depends on the degree and extent of oxidation.. easiest way is check XPS and find C & O percentage.. other option is CNS analyzer..
Yes sir first i have used flakes later i used graphite powder, what you prefer sir flakes or powder.
Flakes take longer to get oxidized.. powder is easy to oxidize, so it tends to form lot of amorphous carbon which is not good in graphene synthesis..
So better use flakes, yield may be low, but you will get good quality graphene.
The easier and quickest way to check the quality of graphite oxide is by XRay analysis. The peak of graphite at around 26 deg should completly disappear. You would instead have a peak at lower angles (around 13-14 deg) indicating the increase in interlamelar distance.
oh ok mam but somebody reported the go peak at 9 degree or 10 degree why its showing like that, whether its a good product or not ?. I want to know the quality of product is depends upon the position of the peak or the intensity of the peak please clarify my doubt.
The position will depend on the separation of the lamellar sheets and this depends on the amount of groups and oxidation you have achieved. You can find a good paper here
http://nanotube.skku.ac.kr/data/paper/JPhysDApplPhys42_065418.pdf
OK now i got it, thanks you mam that link is very informative, i thank everybody for your nice suggestions .
As for the method of Hummers not fully oxidized graphite, the good is to use a pre oxidation of graphite base is P2O5 and other
http://pubs.acs.org/doi/abs/10.1021/cm981085u
ensures better training of the graphite oxide, and after XPS or TG
may be the D over G ratio of Raman give u some idea about quality of pdt. it should be within 0.7 to 0.9
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