Synthesis of Graphene Oxide by Hummers Method
CHECK LIST: Graphite, Sulphuric Acid, Potassium Permanganate (KMnO4), Hydrogen Peroxide (H2O2), Water, Beaker, Measuring Cylinder, Magnetic Stirrer
STEP1: Take Sulphuric Acid (25ml) in Ice Bath and add Graphite (1g) with proper stirring
STEP2: Add Potassium Permanganate(3g) very slowly by keeping the temperature less than 20ºC and stir for more 3 hours (NOTE: You may remove the ice bath after 20 minutes and again setup for STEP3)
STEP3: Add distilled water (50ml) dropwise by keeping the temperature less than 50ºC
STEP4: Add distilled water (100ml) instantly for complete oxidation
STEP5: Add Hydrogen Peroxide (5ml) for the completion of the reaction
RESULTS: Graphene Oxide (GO) colour would be dark brown; UV-VIs spectroscopy absorbance peak would be obtained around 250nm; Raman spectroscopy D band and G band would be obtained at around 1300cm-1 and 1550cm-1 respectively
FACTORS AFFECTING THE SYNTHESIS:
- Concentration of Graphite: The amount of Graphite used for the synthesis of Graphene Oxide (GO) is very important factor; because oxidation penetration on Graphite depends on the concentration of the Graphite in the Sulphuric Acid. Higher the concentration of Graphite, lesser the penetration of oxidation.
- Concentration of Sulphuric Acid: Concentration of Sulphuric Acid is most important in Hummers method. Higher the concentration of Sulphuric Acid, higher the chances of complete exfoliation of Graphite into Graphene Oxide; But also very high chances of unwanted accident.
- Effect of KMnO4: In this method, KMnO4 acts as Oxidizer, Sulphuric Acid functionalize the Graphite surface to add functional groups in the presence of reagent like KMnO4. KMnO4 should be added slowly because it increases the temperature of the reaction and may lead to incomplete oxidation at the end, if poured instantly and not stirred properly.
- Rate of Adding Water: Rate at which water is added for the oxidation matters a lot. InstaNANO suggest you to add water drop wise very slowly to avoid unwanted accidents and good quality Graphene Oxide.
- Role of Hydrogen Peroxide: Main role of Hydrogen Peroxide is to remove the excessive KMnO4 or in other words to stop the reaction.
NOTE: Hummers Method is dangerous and should be done very carefully by wearing the lab coat, hand gloves, eye safety glasses and other lab safety measures; and under the guidance of Lab Incharge