Exfoliation of Graphite Oxide in Propylene Carbonate and Thermal Reduction of the Resulting Graphene Oxide Platelets
β Scribed by Zhu, Yanwu; Stoller, Meryl D.; Cai, Weiwei; Velamakanni, Aruna; Piner, Richard D.; Chen, David; Ruoff, Rodney S.
- Book ID
- 115548000
- Publisher
- American Chemical Society
- Year
- 2010
- Tongue
- English
- Weight
- 399 KB
- Volume
- 4
- Category
- Article
- ISSN
- 1936-0851
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β¦ Synopsis
raphene and graphene-based materials have attracted intensive research interest due to their fascinating properties. The exfoliation of graphite oxide (GO) followed by reduction has provided an affordable route to the large scale processing of graphene-based materials. In particular, the importance of solution-processable graphene oxide (by the exfoliation of GO) has been demonstrated by the fabrication of paperlike films, 3 transparent conductive electrodes, 4Οͺ6 and conductive polymeric 7 and ceramic composites. Since a stable colloidal suspension of graphene oxide platelets is obtained by the simple sonication of GO in water, 9,10 much of the solution processing of graphene oxide reported to date has been carried out in aqueous media. 11 Li et al. reported aqueous dispersions of reduced graphene oxide (RG-O) nanoplatelets by changing the pH to about 10 prior to reduction with hydrazine. The dispersion of RG-O in water at a pH of approximately 7 could be achieved by addition of poly(sodium 4-styrenesulfonate) to the aqueous suspension of graphene oxide platelets prior to addition of hydrazine. The preparation of large-scale graphene oxide dispersions in organic solvents is also highly desirable and may further broaden the scope of applications and facilitate the practical use of graphene-based materials. 11 Paredes et al. stated that the full exfoliation of GO and stable dispersion of graphene oxide could be obtained in N,N-dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP), tetrahydrofuran (THF), and ethylene glycol (EG). Recently, Park et al. reported achieving colloidal suspensions of highly reduced graphene oxide in various organic solvents by diluting the colloidal suspension of RG-O platelets in DMF/H 2 O (9:1) with solvents such as DMF, NMP, ethanol, acetonitrile (AN), and dimethylsulfoxide (DMSO), among others. The dispersion of graphene oxide in chloroform has been realized by transferring surfactant decorated graphene oxide from water to chloroform. Graphene oxide is electrically insulating and various reduction methods have been developed to restore the conjugated network and electrical conductivity of graphene. Reducing agents such as hydrazine or dimethylhydrazine, hydroquinone, and NaBH 4 20,21 have been used to reduce graphene oxide. Cote et al. have demonstrated a flash-assisted reduction of films composed of graphene oxide platelets and their polymer composites, where a flash beam with an energy flux of about 1 J/cm 2 was used to irradiate and heat the samples to over 100 Β°C to trigger thermal reduction. A method involving heating graphene oxide suspensions in water under alkaline conditions has been proposed as a "green" route to suspensions of RG-O. Direct thermal treatment at elevated temperatures provides another method to reduce individual graphene oxide platelets
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