Specific process flow:
Assemble a 250 mL reaction bottle in an ice water bath and add a proper amount of concentrated sulfuric acid? Adding a solid mixture of 2 g graphite powder and 1 g sodium nitrate under stirring;
How many times do you add 6 g potassium permanganate? Control the reaction temperature not to exceed 20℃ and stir for a period of time, then raise the temperature to about 35℃ and continue stirring for 30 minutes? Then slowly add a certain amount of deionized water? After continuous stirring for 20 min, add proper amount of hydrogen peroxide to reduce the residual oxidant? Make the solution bright yellow.
Filter while it is hot, and wash with 5%HCl solution and deionized water until no sulfate radical can be detected in the filtrate. Finally, put the filter cake into a vacuum drying oven at 60℃ and fully dry it? Save for later use.
2.Hummers method
Specific process flow:
Assemble a 250 mL reaction bottle in an ice-water bath, add a proper amount of concentrated sulfuric acid, add a solid mixture of 2 g graphite powder and 1 g sodium nitrate under magnetic stirring, then slowly add 6 g potassium permanganate, control the reaction temperature to be below 10℃, stir in the ice-water bath for 2 h, then take it out and stir at room temperature for 5 d.
The sample was diluted with 5% H2SO4 (mass fraction) solution, stirred for 2 h, then added with 6 mL H2O2, the solution turned bright yellow, stirred for 2 h, centrifuged, and then washed repeatedly with mixed solution of H2SO4 and H2O2 with appropriate concentration and HCl.
Finally, it was washed with distilled water for several times to make its pH~7, and the yellow-brown precipitate obtained was graphite oxide (GO). The sample was fully dried in a vacuum drying oven at 40℃.
The obtained graphite oxide was put into deionized water, ultrasonically treated at 60 W for about 3 hours, and precipitated overnight. The supernatant was centrifugally washed and dried in an oven at 40℃ to obtain graphene oxide with a thin layer.