Fig. 1

Schematic illustration of the synthesis of nGO through modified Hummer’s method. The procedure includes 9 steps: 1) combining 10 gr of Graphite flakes and 110 cc of H3PO4 and 1 L of H2SO4 (98%) 2) stirring the sample mixture for 72 h and gradually addition of KMnO4 3) removing the ice bath and stirring the sample mixture until it became pasty brownish 4) slow addition of 10 cc H2O2 5) addition of 100 mL of water 6) keeping the sample mixture for 48 h for sediment of fillers 7) filtration 8) purification 9) drying (Abbreviations: H3PO4: phosphoric acid/ H2SO4: sulfuric acid/ KMnO4: potassium permanganate/ H2O2: hydrogen peroxide)