Graphene/Iron Oxide Composite Fabrication

Fig. 1 illustrates the graphene/iron oxide composite fabrication model. Accordingly, the entire two electrode electrochemical system includes a cathodic graphite rod and anodic platinum foils set into a flask of electrolyte solution which is placed in an ultrasonic vibrating tank. In the meantime, the mixture of Fe₂(SO₄)₃·xH₂O (7.99 g) and FeSO₄·7H₂O (2.78 g) was dissolved in 150 mL of distilled water. We maintained this mixture solution at 60 °C for 30 min under a slight stirring level of 100 RPM. First, the sharpened graphite rod is located about 1 mm to 2 mm above the electrolyte solution level. The anode platinum foil was embedded at 5 cm depth in the electrolyte solution. The using electrolyte solution is 200 mL NaOH 0.5 M. Secondly, a direct current (DC) source with a voltage of 120 V was applied to two electrodes. The sharpened tip of the graphite rod was descended gradually into electrolytes which induced the plasma zone at the electrolyte touching position under the high asymmetric electric field. Then, the mixture solution of Fe³⁺ and Fe²⁺ was slowly added to the electrolyte solution at a drop rate of 2 mL min⁻¹ when the plasma discharge and ultrasonic vibration were performing. The composites materials of GFs were simultaneously generated by the flow of electrons from the negative electrode to be discharged directly and the solution plasma conditions. This experiment was performed in 75 min. The as-prepared materials were collected by the filtration system using the PVDF membrane with the pore size of 0.2 μm. The resulting powder was washed in distilled water at least 3 times and then dried 24 hours at 80 °C in air. The obtained composite material is denoted as GF and using for further characterization.