GO was prepared by modified Hummers method .
200 mg GO was dispersed in deionized water (200 mL) byul trasonic vibration for 2h. Then, 3g ammonia and 3 mL hydrazine
hydrate (80%) were added.There action was heated to 100 °C and stirred for 2h. Finally, the product was washed and dried to obtain RGO nanosheet.