Economic procedure for facile and eco-friendly reduction of graphene oxide by plant extracts; a comparison and property investigation

Hummer's method which uses concentrated acid and oxidant agents, still is the most productive procedure for production of graphene oxide (GO). However, the reduction of the prepared GO sheets to the reduced graphene oxide (rGO) is the main problem for practical applications. However, the main problem is that prepared GO needs to reduce to graphene for practical applications. Some of the industries where graphene is making an important impact as follows; transport, medicine, electronics, energy, defense and desalination. Conventional methods for reduction of GO, such as thermal annealing or chemical approaches, have been applied frequently. However, they have drawbacks, such as toxic nature of them, their high prices and harmful effects to both environment and human body that make their use undesirable. Here we proposed and tested a green approach including plant extracts for a satisfying reduction of GO to reduced graphene oxide (r-GO) which leads to removing of oxygen containing functional groups. The extracts of Mentha (or Mint) and Tribulus terrestris indicated the moderate antioxidant activities in 2,2-diphenyl-1-picrylhydrazyl (DPPH) test (IC50 = 28 and 33 ppm respectively). After reduction GO by mentioned extracts, the products characterized by XRD, FT-IR, SEM, TEM, Raman and TGA analysis. The obtained results represented that the interaction between GO and Mint extract leads to more efficient reduction of GO in compare to Tribulus terrestris extract. More investigation of Mint extract reduction potential was performed by reducing of GO and Fe3+ ions using Mint extract in the synthesis of rGO/Fe3O4. VSM analysis was a good evidence for suitable reduction of Fe ions and GO, which produced rGO/Fe3O4 nanocomposite with superparamagnetic property. (C) 2019 Elsevier Ltd. All rights reserved.