Graphene oxide is first synthesized using a method called the Modified Hummer's method . To begin this procedure, 50 mL of sulfuric acid (Sigma Aldrich) is added to a beaker cooled by an ice bath set at a temperature lower than 20 ˚C. 2 grams of graphite powder (Sigma Aldrich) is added and the solution is stirred at 500 rpm. 5 grams of potassium permanganate (Sigma Aldrich) is added very slowly to the reaction since the reaction is exothermic. After a few minutes, the ice bath is replaced by a heater set at 40 to 50 ˚C. After 3 hours, the ice bath is placed again and 200 mL of distilled water is added to the reaction dropwise carefully. After 15 minutes, 150 mL of distilled water is added again. Then 10 mL of hydrogen peroxide (Sigma Aldrich) is added slowly to stop the reaction. The solution is then centrifuged at 4000 rpm to separate unwanted from the solution. The precipitate is then washed by 1:9 aqueous hydrochloric acid (Sigma Aldrich) to remove the sulfate ions, followed by washing by distilled water. The resulting mixture is then dried overnight in a 60 ˚C oven to obtain graphene oxide powder.