Deoxygenation of graphene oxide using biocompatible reducing agent Ficus carica (dried ripe fig)

Graphene, the wonder material, has become popular among nanomaterial investigators. The path-breaking discovery of graphene was made by Geim and co-workers [ 1 ]. Since then there has been active interest in graphene. Remarkable features such as large surface area (2620 m 2 g −1 ), superior Young’s modulus (1.0TPa), exceptional thermal conductivity (~ 5100 W m −1 K −1 ), unique chemical strength and large electron movement (2.0 × 105 cm 2 v −1 s −1 ) are shown by the graphene sheets [ 2 ]. These outstanding features of graphene initiate new ways for multidimensional applications in different segments of technology. They include applications in catalyst engineering [ 3 , 4 ], lithium-ion batteries [ 5 ], chemically derived sensors [ 6 ], biosensors [ 7 ], anti-bacterial activities [ 8 ], delivery of drugs [ 9 ], solar cells [ 10 ], super capacitors [ 11 ], touch panels [ 12 ], electromagnetic shielding application [ 13 ], water purification [ 14 ], and absorption of non-aqueous fluids oils, olefins, aromatic compounds, dyes and organic solvents [ 15 , 16 , 17 , 18 ]. Due to above-mentioned applications, several methods have been investigated to synthesize graphene. Chemical reduction of graphene oxide (GO) is considered as a superior method for large scale production. The cost is affordable, and time required is of short duration. Identification of green reducing agent for this work is necessary. There onwards, many reductants have been applied for reducing GO. Hydrazine hydrate (N 2 H 4 .H2O), hydrogen bromide (HBr), hydriodic acid with trifluoroacetic acid (HI, TFA), phenol, p -toluenesulfonic acid (PTSA) and sodium borohydride (NaBH 4 ) have been employed as deoxygenating agents. However, most of these chemicals have limitations as their by-products are hazardous for biosphere. Hence, sophistication is required in using these chemicals. The presence of harmful by-products may greatly increase production costs on industrial scale [ 19 ]. Despite precautions the final product may contain remnants of these harmful chemicals. Its use may not be advisable in several applications such as biomedical field or water purification. To overcome these obstacles, investigators have concentrated more on identifying environmentally suitable reducing agents with higher reducing ability than chemical reducing agent. Consequently, there is an actual need for simple, environment-friendly and cost-effective method for production of graphene. These problems may be solved by green reduction. Researchers have presented various eco-friendly reductants in recent years [ 20 ]. They include antioxidants, microorganisms, extracts of plants, vitamins, organic acids and proteins. Such reductants are termed as “green reducing agents” as they are eco-friendly and cost-effective. Further attempts should, however, continue to identify an inexpensive, efficient as well as green deoxygenating agent for production of graphene chemically at large scale.