The versatility of the chemical route for the preparation of graphene

The versatility of the chemical route for the preparation of graphene

The versatility of the chemical route for the preparation of graphene
materials from graphite
Rosa Menéndez
Instituto Nacional del Carbón, CSIC, Apartado 73, 33080 Oviedo, Spain
[email protected]
The chemical route is generally regarded as the best alternative for the preparation of
graphene on a large scale [1]. The oxidation of graphite is currently based on the
Hummers [2] or Brodie method [3]. For the subsequent steeps of exfoliation and
reduction there are several options [4] that will determine the final characteristics of the
graphene.
By using graphites of different crystalline structure it is possible to prepare graphene
oxides and consequently graphenes of different sheet size, structure and properties [5].
Thus graphene materials can be tailored for their subsequent applications [6]. Moreover,
using the same graphite as parent material, but varying the oxidation process, the
structure of the graphene oxide in terms of percentage, type and distribution of the
oxygen functional groups can also be adjusted. All of these factors have a special
incidence on the effectiveness of the subsequent reduction process and on the final
structure of the graphene produced. However not only does the oxidation method have
an effect on the material but also the time during which ultrasounds are applied to
produce the exfoliation of the graphite oxide [7]. Graphites depending on their
crystalline structure, have an optimum time for achieving a maximum product yield
with the largest sheet size [5].
Among the different technologies for the reduction of the graphene oxide to graphene,
the application of temperature has emerged as one of the easiest and more effective
ways. This has the additional advantage that it can be applied directly to the graphite
oxide, so that exfoliation and reduction occur in a single step [8]. The use of different
temperatures yields graphene materials with a range of structures and properties (i.e.
different electrical and thermal conductivities, very different surface areas) [9]. Also
worth mentioning is the possibility of restoring the pristine graphite structure of the
graphene sheets by using of CO at low temperature [10].
To summarize, more than 50 graphene materials with different sheet sizes, structures
and properties were prepared by the composites group at INCAR-CSIC [5, 6, 8, 9, 10].
Selecting one or another will depend on the final application. In fact, some of these
materials exhibit an excellent performance in energy storage devices [9], in transparent
conductive materials for solar cells or LEDS [11] and as proactive supports in catalysis.
However, no beneficial effect was observed when they were combined with TiO2 in
photo catalytic processes because of the absence of the expected synergetic effects.
These activities are supported by CSIC, Local, National and European Programs, with
the participation of Spanish industries (CSIC, I-LINK0459; FICYT, Ref. COF11-34;
MINECO, Ref. MAT2010-16194, INNPACTO, Ref. IPT-2011-0951-390000 and
CONSOLIDER INGENIO 2010, Ref. CSD2009-00050; EC, Ref. RFC-BR-12008).
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[2] W. S. Hummers, R. E. Offerman, J. Am. Chem. 80 1958, 1339.
[3] B. C. Brodie, Philos. Trans. R. Soc. London 179, 1859, 249.
[4] D. R. Dreyer, S. Park, C. W. Bielawski, R.S. Ruoff. Chem. Soc. Rev. 39, 2010, 228.
[5] C. Botas, P. Álvarez, C. Blanco, R. Santamaría, M. Granda, P. Ares, F. RodríguezReinoso, R. Menéndez, Carbon 50, 2012, 275
[6] C. Botas, P Álvarez, C. Blanco, M.D. Gutiérrez, P. Ares, R. Zamani, J. Arbiol, J.R.
Morante, R. Menéndez, RSC Adv. 2, 2012, 9643.
[7] S. Pan & I.A. Aksay. ACS nano 2011; 5 (5): 4073–4083.
[8] C. Botas, P. Álvarez, C. Blanco, R. Santamaría, M. Granda, M.D. Gutiérrez, F.
Rodríguez-Reinoso, R. Menéndez, Carbon 52, 2013, 476
[9] Z. González, C. Botas, P. Álvarez, S. Roldán, C. Blanco, R. Santamaría, M. Granda,
R. Menéndez. Carbon 50, 2012, 828.
[10] A. Pulido, P. Concepción, M. Boronat, C. Botas, P. Álvarez, R. Menéndez, Avelino
Corma. J. Mater. Chem. 22, 2012, 51.
[11] X. Díez-Betriu, S. Álvarez-García, J. Sánchez-Marcos, R. Jiménez-Riobóo, C.
Prieto, C. Botas, P. Alvarez, R. Menéndez, H. Varela-Rizo and A. de Andrés.
GrapHEL-A European Conference/Workshop, 27-30 septiembre 2012,
Grecia
Mykonos,