Dear Researcherrs,
I was preparing Graphite oxide using hummers method outlined here.
http://www.omicsonline.org/open-access/a-simple-approach-to-stepwise-synthesis-of-graphene-oxide-nanomaterial-2157-7439.1000253.pdf
When I diluted the solution after 3 days of oxidation the color changed to brown. Later When I added H2O2 with stirring, my solution changed color from brown to yellow then to Green with increasing amounts of H2O2. Now its light green. Video here
https://youtu.be/NthPpaVCgd4
. Don't mind the sound. Fume hood makes a lot of noise
I want to know what happend? Has my reaction progressed in the right way?
Hi Hasim,
After addition of H2O2, the solution colour turned into yellow determines that reation is completed and graphite is converted into graphite oxide. If you add additional H2O2 means you are oxidizing the Mn speceis, present in the system and that is the reason behind the green colouration of the mixture.
Agreed with Sujoy Sarkar . The addition of H2O2 reduceds higher oxidation staes to water soluble Mn2+.However excess addition of H2O2 results oxidation of Mn2+ to Mn3+ . This Mn3+ responsible for green colour.
Asmita Dutta if you get any solutions to this particular problem please do post it here
Hashim Shah
It depends on the type of graphite. If you are using graphite powder with a particle size of around 24 micrometers, which was purchased from Sigma Aldrich, then the color is normal, and it won't change to yellow. When I used another graphite powder source, the final color turned yellow in each run of the synthesis. In addition, the chemical properties of your sample matter! As long as it has a desirable oxidation degree, everything is fine!
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