Investigating the influence of surfactants on the stabilization of aqueous reduced graphene oxide dispersions and the characteristics of their composite films

Fernández-Merino, M.J.; Paredes, J.I.; Villar–Rodil, S.; Guardia, L.; Solís‐Fernández, Pablo; Salinas-Torres, David; Cazorla‐Amorós, Diego; Morallón, Emilia; Martı́nez-Alonso, A.; Tascón, J.M.D.

doi:10.1016/j.carbon.2011.10.039

Cited by 98 publications

(60 citation statements)

References 46 publications

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“…peaks at 225-230 and *300 nm assigned to p-p* transitions of C-C and n-p* transitions of carbonyl groups (Marcano et al, 2010;Ramesha et al, 2011). The GE absorption peak at 266 nm corresponds to p-p* transitions of C = C chromophore, indicating an increased electronic conjugation of the GE sheets due to the reduction process (Fernández-Merino et al, 2012). The same transition is observed in GRA spectrum.…”

Section: Infrared Spectroscopysupporting

confidence: 56%

Comparison as Effective Photocatalyst or Adsorbent of Carbon Materials of One, Two, and Three Dimensions for the Removal of Reactive Red 2 in Water

Pérez-RamírezEduardo

Rosa-ÁlvarezGuadalupe

Salas

et al. 2015

Environmental Engineering Science

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Photocatalytic degradation and removal by adsorption of the Reactive Red 2 (RR2) dye in the presence of different pristine and functionalized one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) carbon structures were investigated and compared, considering also the loading of catalyst/adsorbent. Previous to photocatalytic and adsorption evaluation, all carbon materials were characterized to verify functionalization, structural changes, and surface properties useful in the removal of this pollutant in water. Materials were analyzed by Raman and infrared spectroscopies, transmission electron microscopy, and besides, the pH of the point of zero charge (pH pzc ) was determined by potentiometric titrations, and band gap by ultraviolet-visible spectroscopy through Tauc plot. Removal of RR2 increases with the load of carbon materials. One-dimensional materials showed better performance in the decolorization of RR2 dye, removing the whole color of the solution. RR2 removal values obtained by the photocatalytic and adsorption processes are very similar. Thus, the adsorption process predominates over the photocatalytic activity, only the samples of graphene and graphene oxide present slight photocatalytic activity. The adsorption process was strongly influenced by the carbon material dimension. However, other factors like surface oxygenated groups, surface area, and the shape of the carbon structures, as well as the structure and nature of the dye also play an important role in this process. Experimental adsorption data of all carbon materials were best fitted to pseudo second-order kinetic model, and, it is concluded that physisorption with strong interaction is the process by which carbon materials adsorb to the dye. Thus, the mechanism of RR2 adsorption on carbon materials is by the aromatic rings of the RR2 and p delocalized electrons on carbon materials.

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Section: Infrared Spectroscopysupporting

confidence: 56%

Comparison as Effective Photocatalyst or Adsorbent of Carbon Materials of One, Two, and Three Dimensions for the Removal of Reactive Red 2 in Water

Pérez-RamírezEduardo

Rosa-ÁlvarezGuadalupe

Salas

et al. 2015

Environmental Engineering Science

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“…The conductivity significantly decreases to 1.28 S m À1 and 15.54 S m À1 in solution-cast graphene/PVP and graphene/PSA films, respectively. This clearly indicates that the excess dispersant hinders the connectivity of graphene sheets by increasing contact resistance (a detailed list of electrical conductivity measurements on rGO and pristine graphene films in the existing literature is presented in Table S1 [3,4,[16][17][18]30,[37][38][39][40]). …”

Section: Effect Of Dispersant On the Electrical Conductivity Of Graphmentioning

confidence: 99%

“…S1b). Vacuum filtration of graphene dispersions is already established as a method of washing off dispersants [16,17]. We applied a simple re-dispersion method to make a liquid sample of graphene from the solid film.…”

Section: Dispersant Removal Techniquesmentioning

confidence: 99%

“…The second method is vacuum filtration, which is widely used to make nanomaterial films [16][17][18][30][31][32]. Graphene dispersions were vacuum filtered (Fig.…”

Section: Dispersant Removal Techniquesmentioning

confidence: 99%

“…Multiple studies on both pristine graphene [16] and reduced graphene oxide (rGO) [17] show that the presence of various ionic, non-ionic, and zwitterionic surfactants in cast graphene films increases sheet resistivity, presumably by increasing the inter-sheet contact resistance [17]; accordingly, the removal of residual solvent or surfactants by annealing increases the film conductivity [3,4,11,18]. These results suggest that removal of dispersants from the dispersion itself (either in the bulk or on the graphene surface) can be useful for increasing electrical conductivity in graphene films and buckypapers; this issue of contact resistance would also affect the maximum attainable electrical conductivity in graphene-filled polymer nanocomposites.…”

Section: Introductionmentioning

confidence: 99%

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