Synthesis of rGO/ZnO Composite (reduced Graphene Oxide/Zinc Oxide)
CHECK LIST: Graphene Oxide (GO), Zinc Acetate (Or Zinc Nitrate), Sodium Hydroxide, Hydrazine Hydrate, Deionized Water, Sonicator, Micropipette, Magnetic Stirrer, Round Bottom Flask and Reflux Setup
STEP1: Add Graphene Oxide (500mg) in deionized water (150ml); and sonicate for 40 minutes
STEP2: Add Sodium Hydroxide (4g) in deionized water (100ml); add it in GO solution; and sonicate again for 20 minutes.
STEP 3: Add Zinc Acetate (2.19g) in deionized water (100ml); and add it drop wise in GO solution.
STEP4: Add Hydrazine Hydrate (3ml of 10%); and setup reflux at 80ºC for 24 hours.
STEP5: After 24 hours remove the reflux; filter out the rGO/ZnO composite; and wash with deionized water several times.
RESULTS: Reduced Graphene Oxide colour would be black; Raman spectroscopy will show a peak around 440cm-1. You will also get a peak around 380nm in UV-Vis Spectrosocpy
FACTORS AFFECTING THE SYNTHESIS:
- Concentration of Graphene Oxide: The first main ingredient for the synthesis of rGO/ZnO composite is Graphene Oxide. As much concentration we take initially, that much amount rGO we get at the end of the process. But much higher amount of Graphene Oxide can leads to incomplete reduction and thus bad quality final product.
- Concentration of Zinc Precursor: Second main salt in this synthesis is Zinc Acetate (Or Zinc Nitrate). If concentrate of Zinc Acetate is increased, then amount of reducing agent (i.e. Hydrazine Hydrate) should also be increased. Much higher concentration of Zinc Acetate will lead to bigger particles of Zinc Oxide in the final composite.
- Concentration of Hydrazine Hydrate: Hydrazine Hydrate acts as the reducing agent in synthesis method. For the optimum reduction of Graphene Oxide and Zinc Acetate, optimum quantity of Hydrazine Hydrate is needed.
- Effect of Temperature: Temperature plays an important role in speeding up any reaction. High temperature synthesis give us fine product quality by consuming less time.
- Why Reflux: Reflux is a very good technique, when we want to give temperature to the solvents just below their boiling point. In this synthesis method, if we do not use reflux and direct heat the solution for 24 hours. Then all the water will be evaporated within few hours and only solid non-reduced GO will be left in the RB flask.
NOTE: All the experiments should be done under the guidance of lab Incharge; and proper lab safety instructions.in