Scalable Syntheses of Graphene Oxide and Reduced Graphene Oxide using Cascade Design Oxidation and Highly Basic Reduction Reactions

So our research scope is oxidation and reduction technology on producing the graphene and reducing graphene oxide nanomaterials. So we develop a protocol for chemical oxidation reaction with the optimized safety and efficiency.

Technologies that improve safety and sensing various oxidation reactions, and alkaline production reaction are important to the production of graphene oxide and reduced graphene oxide.

Scale of graphene oxidation reaction require a safe and efficient protocol. Beside host efficiency, echo brand needs and graphene reducting and that is in chemical reduction reaction.

We present cascade design, oxidation reaction, and harnessing exothermic energies for cell heating reaction, saving chemicals, energies, and time. Reduction reaction using basic ammonia is simple and effective for nonstop reduced graphene oxide.

Our laboratory will develop the protofilm of oxidation reduction reaction for the scale production and protocol application of graphene based materials, especially addressing the side graphene is useful for water purification, water catalyst, energy storage and production.

[Narrator] To begin, add five grams of graphite powder to a 50 milliliter glass beaker, and add 50 milliliters of 97% sulfuric acid to the beaker. Stir the three suspensions of graphite and sulfuric acid magnetically at ambient conditions for at least one hour. In a 250-milliliter glass Erlenmeyer flask, add 100 milliliters of 97% sulfuric acid. Slowly add 10 grams of potassium permanganate to the sulfuric acid solution under magnetic stirring to dissolve and prepare about 100 milliliters of manganese and sulfuric acid solution. Slowly pour one previously prepared graphite and sulfuric acid suspension into the manganese and sulfuric acid solution under magnetic stirring in the 250-milliliter glass Erlenmeyer flask. After nine minutes in a water bath, continue stirring the reaction mixture in ambient conditions. Allow the exothermic reaction temperature to peak between 48 and 52 degrees Celsius, and gradually return to room temperature. Stir all three mixtures of graphite, manganese, and sulfuric acid magnetically in ambient conditions. Next, carefully pour the first Erlenmeyer flask of graphite, manganese, and sulfuric acid mixture into 1,080 milliliters of water under agitation. Use an infrared thermometer to measure the reaction temperature, which rises to approximately 59 degrees Celsius. Then slowly add the second Erlenmeyer flask of graphite, manganese, and sulfuric acid mixture to raise the temperature to about 80 degrees Celsius. Add the third Erlenmeyer flask of mixture to increase the temperature to approximately 94 degrees Celsius. Gradually pour 450 milliliters of 5% hydrogen peroxide solution into the beaker, observing a slight temperature rise from the exothermic reaction. Now pour the entire reaction mixture into 50 milliliter centrifuge tubes. Centrifuge at 1,500G for five minutes at ambient temperature. Collect the sedimented solids to mix them with one liter of 5% hydrochloric acid solution. After agitating the acidic suspension for at least one hour, centrifuge and wash the suspension until the supernatant solution reaches pH four. Use a vacuum filtration system with pure water to wash the sedimented graphite oxide solid. Next, dry the washed graphite oxide slurry in a drying oven set to 80 degrees Celsius. Then using a stainless steel or ceramic mortar and pestle, grind the dried material to produce a graphite oxide powder. Use scanning electron microscopy and energy dispersive X-ray spectroscopy to characterize the obtained graphite oxide and graphene oxide. Drop 25 to 28% ammonia solution gradually into the aqueous dispersion of graphite oxide until the pH reaches 10. Sonicate the dispersion using an ultrasonic probe set to 100 watts power with a continuous cycle and amplitude of 80%. Pour the one liter dispersion of graphene oxide into a one liter round glass reactor. Add 111 milliliters of 25 to 28% ammonia solution to raise the pH above 11 and make the mixture highly basic. Heat the reaction mixture to 90 degrees Celsius without stirring. Then filter the reduced graphene oxide mixture using filter fabrics or cellulose filter paper and collect the hydrogel in a plastic box for storage. Use scanning electron microscopy and energy dispersive x-ray spectroscopy to characterize the reduced graphene oxide hydrogel. Finally, disperse 0.1 gram of reduced graphene oxide hydrogel in 300 milliliters of water. Use agitation followed by sonication to ensure a homogeneous dispersion of RGO nanosheets, indicating good aqueous dispersity. The x-ray diffraction pattern of graphite oxide powder revealed a peak at 10.8 degrees, corresponding to inter-sheet distance of 8.19 angstroms and a peak at 42.2 degrees. SEM images confirmed the multi-layer structure of graphite oxide particles and elemental mapping displayed uniform distributions of carbon and oxygen atoms. EDS spectrum and elemental analysis of graphene oxide indicated 64.02% carbon atoms and 35.98% oxygen atoms, giving a CO-atomic ratio of 1.78. SEM images of go nanosheets exfoliated from graphite oxide at 1,000 parts per million concentration revealed successful separation into thin sheets. XRD patterns of reduced graphene oxide hydrogel and powder revealed a broad peak at 27.7 degrees for hydrogel, while powder exhibited sharper peaks at 10.1, 26.6, and 42.6 degrees. SEM images of dehydrated RGO hydrogel revealed non-stacked nanosheets and porous morphology of assembled RGO structures. Elemental mapping of the RGO hydrogel structure demonstrated uniform distributions of carbon and oxygen atoms throughout the matrix, with a CO-atomic ratio of 4.16. SEM images of dehydrated RGO nanosheets revealed a wrinkled morphology and thin sheet structure.