First, some clarifications:
- Graphene is technically only "flat" like a lattice wire one atom thick. Ten or more layers one atom thick ar Graphite. Layers of graphene one on top of the other are graphite AKA #2 pencil lead1
- Graphite is available in various forms and can be used to produce graphene.
- Graphene oxide is a water-soluble "flaked" form of graphene that has a spongelike quality and the ability to adsorb and absorb molecules according to the chemical properties of graphene, H2O, and whatever else.
- Graphene aerogel (pictured below) is a mixture of carbon nanotubes and graphite; the end result is an extraordinarily lightweight and strong substance that has unique thermal properties.
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| photo credit: extremetech.com |
The first method of producing graphene in actual "sheets" not bound to any tape surface (see article below) requires graphene oxide. There are several ways to get graphene oxide: one is to purchase prepared vials of graphene oxide -- which can be expensive, but easy. The other is to make it yourself from various industrial suppliers -- to hack the composition of the graphene yourself using chemistry and a recipe of ingredients -- sulfuric acid, sodium nitrate, potassium permanganate, etc.
A Recipe for Graphene Oxide
Materials needed (can be obtained via Amazon):* Not recommended to double this recipe unless you're a certified lab with professionals, or in a very safe preparation space.
- 50 grams graphite, pre-powdered or shaved into powder form
- 25 grams sodium nitrate (NaNO3)
- 150 grams potassium permanganate (KMnO4)
- 1.15 liters sulfuric acid (H2SO4)
- 2.4 liters of water (H2O)
- Hydrogen Peroxide (H2O2)
- large chemical-reaction-friendly container (capable of holding 8 - 10 liters)
- larger leakproof bowl for "ice bath"
- stirring stick
- enough ice for an ice bath around the chemical-reaction friendly container
- thermometer
- safety equipment: (goggles, gloves, etc)
Directions:
1. In the leak-proof bowl prepare the ice bath and place the chemical-reaction-friendly container in it. The production of graphene oxide releases a lot of thermal energy and the ice bath is imperative!
2. Pour the sulfuric acid into the chemical-reaction-friendly container.
3. Mix the powdered graphite and sodium nitrate slowly into the sulfuric acid, stirring continually.
4. Add the potassium permanganate to the mixture in a very slow drizzle.
WARNING -- Potassium permanganate is a powerful oxidizer that can burn or stain skin and other organic materials such as clothing upon contact. When mixed with sulfuric acid, it produces a highly explosive manganese oxide, so every safety measure should be taken. Make sure the maximum temperature is not exceeded.5. After the potassium permanganate has been slowly and carefully dissolved into the mixture, remove the ice-bath and allow the temperature to come up to 35 degrees Celsius. Maintain this temperature for ~ 30 minutes, and watch as the solution thickens and gases reduce. At around the 20 minute mark, expect the solution to be brownish-gray and beginning to thicken to a more pasty consistency.
6. After 30 minutes have passed, slowly and carefully add 2.4 liters of water into the mixture while stirring. Adding H2O at this point should create an exothermic reaction, increasing the temperature of the mixture to close to 100 degrees Celsius; a large volume of gas will be released in a violent reaction! Maintain the temperature at 98 degrees Celsius for another 15 minutes. At this point the solution should be a murky brown.
7. After maintaining the temperature for 15 minutes, further dilute the mixture to a total of 7 liters of fluid with warm water. Add 3% hydrogen peroxide in order to reduce the leftover permanganate. With the addition of hydrogen peroxide, the mixture should turn bright yellow.
8. Filter the mixture while still warm. The filter will take a yellow-brown color. Wash the filter cake three times with a total of 10 liters of warm water.
9. Disperse the resulting graphite oxide in at least 12 liters of water. The quickest way produce dry graphite oxide is by using a centrifuge to "dry" the mixture; but for the average at-home experimenter, a centrifuge is likely not practical. As an alternative means, the water containing graphite oxide may be heated to 40 degrees Celsius and left to evaporate. A large, flat and thin "pool" of water for evaporation works best since the rate of evaporation is correlated to the surface area upon which it is allowed to evaporate.
That's it! After the water has been centrifuged-away or evaporated the remaining substance should be pure flakes of graphene oxide -- capable of cleaning up radioactive waste. Higher grades can be distinguished by brighter yellow flakes. If you messed something up, the end result may be dark green or black. This is not "useless" oxide but simply less effective at screening pollutants; the "percent Hydrogen Peroxide" can be altered slightly to obtain more "pure" graphene oxide flakes, but -- of course -- extra precautions should be taken when repeating the experiment any variables altered.
Recipe for Graphene (using the Graphene Oxide we just made)
DVD burner - LightScribe technology approach
Graphite oxide is water-soluble, so after mixing it with water, carefully pour it on a DVD drive. Make sure the graphite oxide solution is evenly distributed on the plastic surface of the disc. After the solution has dried and created a film of graphite oxide on the disc, place the disc into the DVD drive, film-side down. Use the LightScribe software to burn in the layer of oxide. The areas of the film which come into contact with the laser beam will be turned into graphene. What actually happens is a reduction reaction which reduces graphite oxide back into graphene. The resulting graphene layer should be carefully removed from the disc and cut into appropriate sized pieces.
Recipe for Graphene
Pencil & Tape Method (for electrical circuitry hacking)Believe it or not, it is possible to create graphene with some pencils and simple Scotch tape. Graphene in this form isn't quite as useful as pure sheets, but can be used to demonstrate some of the electrical properties of nanoscale graphene.
Materials needed:
- 2 pencils, sharpened
- any kind of transparent tape
Directions:
1. Lay a piece of tape flat on a surface such
that the sticky side faces up. You may wish to fold over each end of
the tape to adhere to a base surface.
2. Rub together the two sharpened pencils' sharpened tips with enough pressure to make it "snow" graphite on the tape.
3. Repeat the process until a thin gray powder of graphite is barely discernible.
4. Take a piece of "clean" tape and place it sticky-side face-down on the layer of graphite snow, and pull apart gently
5. Repeat the process a few times -- until you're pretty sure that you're just sticking and un-sticking bare tape.
That's
it. Your final "peel" of tape should have a fine layer of graphene
atoms bound along the tape.
1. Some time before 1565 (some sources say as early as 1500), a large deposit of graphite was discovered on the approach to Grey Knotts from the hamlet of Seathwaite in Borrowdale parish, Cumbria, England. Chemistry was in its infancy and the substance was thought to be a form of lead. Consequently, it was called plumbago (Latin for "lead ore").The black core of pencils is still referred to as lead, even though it never contained the element lead. The words for pencil in German (Bleistift), Irish (Peann Luaidhe), Arabic (قلم رصاص qalam raṣāṣ), and other languages literally mean lead pen.
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