Progress in the functional modification of graphene/graphene oxide: a review

Abstract

Graphene and graphene oxide have attracted tremendous interest over the past decade due to their unique and excellent electronic, optical, mechanical, and chemical properties. This review focuses on the functional modification of graphene and graphene oxide. First, the basic structure, preparation methods and properties of graphene and graphene oxide are briefly described. Subsequently, the methods for the reduction of graphene oxide are introduced. Next, the functionalization of graphene and graphene oxide is mainly divided into covalent binding modification, non-covalent binding modification and elemental doping. Then, the properties and application prospects of the modified products are summarized. Finally, the current challenges and future research directions are presented in terms of surface functional modification for graphene and graphene oxide.

Fig. 1. Carbon allotropes: graphene to fullerene, nanotubes and graphite. This figure has been reproduced from ref. 19 with permission from Springer Nature, Copyright 2007.

Fig. 2. Oxidation of graphene sheet to form graphene oxide. This figure has been reproduced from ref. 43 with permission from Chem. Rev., Copyright 2016.

Fig. 3. Preparation of graphene oxide.

Fig. 4. Schematic synthesis of graphene oxide by the modified Hummers' method. This figure has been reproduced from ref. 53 with permission from Chem. Mater., Copyright 1999.

Fig. 5. Images of isolated graphene oxide and graphene sheets. (a) AFM image of graphene oxide sheets on freshly cleaved mica, the height difference between two arrows is 1 nm, indicating a single graphene oxide sheet; (b) AFM image of water-soluble graphene on freshly cleaved mica; the height difference between two arrows is 1.2 nm; (c) AFM image of large graphene oxide sheets on mica, small holes in the sheets are caused by over-exposure to sonicaion; (d) TEM image of a partially folded water-soluble graphene sheet. This figure has been reproduced from ref. 61 with permission from Nano Lett., Copyright 2008.

Fig. 6. Schematic of solution-processible SDBS–graphene synthesis by in situ reduction with SDBS as the stabilizing agent. This figure has been reproduced from ref. 53 with permission from Nano Lett., Copyright 2007.

Fig. 7. TiO₂–graphene composite and its response under UV-excitation. This figure has been reproduced from ref. 69 with permission from ACS Nano, Copyright 2008.

Fig. 8. Diazonium reaction and subsequent click chemistry functionalization of graphene sheets. This figure has been reproduced from ref. 77 with permission from Chem. Mater., Copyright 2011.

Fig. 9. Synthetic route of polystyrene graft graphite oxide (GO/PS). This figure has been reproduced from ref. 80 with permission from Polymer, Copyright 2011.

Fig. 10. Preparation of polymer–graphene composites. This figure has been reproduced from ref. 81 with permission from J. Colloid Interface Sci., Copyright 2017.

Fig. 11. Preparation route and reaction conditions for the target hydroxy-based functionalization graphene oxide. This figure has been reproduced from ref. 88 with permission from J. Colloid Interface Sci., Copyright 2017.

Fig. 12. Schematic of the functionalization method. This figure has been reproduced from ref. 89 with permission from Chem.–Eur. J., Copyright 2014.

Fig. 13. Exfoliation process of graphite and stabilization of graphene though the π–π interaction with tetrapyrene derivative. This figure has been reproduced from ref. 91 with permission from R. Soc. Chem., Copyright 2016.

Fig. 14. Schematic illustration of aqueous dispersions of (A) GO, (B) GO–PDI and (C) GO–PyS through π–π interaction and (D) co-assembly of negatively charged ssDNA-G sheets and positively charged cytochrome c produces co-intercalated multifunctional layered nanocomposites. This figure has been reproduced from ref. 93 with permission from Adv. Mater., Copyright 2009.

Fig. 15. (a) Structure of graphene oxide (GO) and DXR, UV visible spectra (b) and FTIR spectra (c) of DXR, GO, and GO–DXR. This figure has been reproduced from ref. 94 with permission from Nano Lett., Copyright 2011.

Fig. 16. Transformation of the hydrophilic rGO into an organophilic rGO/polymer composite using an amine terminated polystyrene. This figure has been reproduced from ref. 95 with permission from J. Mater. Chem., Copyright 2010.

Fig. 17. Synthesis of well-dispersed graphene by electrostatic repulsion. This figure has been reproduced from ref. 96 with permission from Nature Publishing Group, Copyright 2008.

Fig. 18. Detailed growth process of N-doped graphene by thermal annealing treatment. This figure has been reproduced from ref. 101 with permission from Catalysis, Copyright 2015.

Fig. 19. Synthesis of N-doped graphene by electrostatic repulsion. This figure has been reproduced from ref. 102 with permission from Nano Lett., Copyright 2009.