Hi Wei,

What is the electrolyte that you used for anodic exfoliation? In my opinion the yellow colour is due to the decomposition of the electrolyte. In case of electrochemical exfoliation of graphite into graphene/graphene oxide, you'll observe the black coloured graphitic material is coming out of the graphite electrode. You won't get homogeneous dispersion of exfoliated graphene or graphene oxide during the electrochemical process but in your pictures, the solution looks very homogeneous. There's no graphene oxide in your solution but the colour is due to electrolyte decompostion.

I agree, the question of electrolyte is important. Also, what was the counter electrode?

About the color of the solution, it's true that it should look more darkish, but even such yellow-orange tones I see for very small GO concentrations. Check for example the Figure 9 (and 11) in the recent review below. In order to be truly sure if you have GO or not, check with Raman!Article Graphene Oxide: Strategies for Synthesis, Reduction and Fron...

Hi Dear Khaled,

Thank you! My electrolyte is 50 mM Na2SO4. The counter electrode is Ti/MMO (Ti based mixed metal oxide, IrO2 and Ta2O5). So I think the yellow color is originated from the electrode. I found from one paper published on JACS, the authors used graphite foil as anode to produce graphene (they called graphene not graphene oxide because O content is low).

Title: Exfoliation of graphite into graphene in aqueous solutions of inorganic salts

Thanks!!

Hi Wei,

I'm aware of the article you mentioned as I'm the lead author in that paper. The material we got through anodic exfoliation is high quality graphene

Hi Khaled,

Thank you! Very glad to get suggestions from you! I still have another question. Is it possible to get graphene in Na2SO4 electrolyte using graphite without high purity? Can graphite felt be used as anode to produce graphene?

Besides, anodization is also a method to introduce oxygen-containing groups to carbonaceous materials. In my experiment, I use anodization to introduce oxygen-containing groups to graphite felt surface (50 mM Na2SO4 electrolyte, 100 mA, cell voltage of ~3.8V). If I increase the cell voltage and operation time, will there be more graphene (or graphene oxide) in solution? I was wondering of this because it possibly means the change of operation parameters could change the purpose of experiment from oxidize carbon electrode to exfoliate electrode to produce graphene.

Thanks!

Wei

Hi Dr. Rodriguez

Thank you! I download the paper and found the Fig. 9. It is helpful to me.

Hi Wei,

It is possible to get graphene oxide in Na2SO4 electrolyte. Please check the following papers for graphene oxide preparation by electrochemical methods:

1. Electrochemically Exfoliated Graphene and Graphene Oxide for Energy Storage and Electrochemistry Applications

2. One-step electrochemical synthesis of nitrogen and sulfur co-doped, high-quality graphene oxide

3. Electrochemically Exfoliated Graphene and Graphene Oxide for Energy Storage and Electrochemistry Applications