Reduction efficiencies of natural substances for reduced graphene oxide synthesis

Synthesis of graphene by reducing graphene oxide is the most propitious route for bulk graphene production. Reduction using eco-friendly techniques is more feasible to alleviate toxic chemicals use. Hence, determining the reduction potency of natural substances is vital for further development in the rGO synthesis process. In this work, an experimental investigation was carried out to determine the reduction efficiencies of various natural and thermal reduction techniques. The results were compared with GO reduced with synthetic routes. To ensure accurate determination of reduction potential, constant reaction parameters and the same GO batch synthesized were used. Thorough sample characterization was carried out using FTIR, XPS, FESEM, Raman spectroscopy, XRD and sheet resistance measurements. Results showed that among natural substances, tea powder showed better reduction efficiencies with 13 folds increase in electrical conductivity, whereas synthetic routes showed more than 29 folds increase in the electrical conductivity values as compared to unreduced GO samples. The C/O ratio quantified from XPS analysis was found to be 2.83, 2.98, 3.88 and 6.34 for reduction carried out using lemon extract, coffee, tea powder and direct thermal treatment, respectively. Based on the results, an eco-friendly reduction route using natural substances has the potential for efficient reduction; however, it needs further optimization.