Ultrafast sol–gel synthesis of graphene aerogel materials

Abstract

Graphene aerogels derived from graphene-oxide (GO) starting materials recently have been shown to exhibit a combination of high electrical conductivity, chemical stability, and low cost that has enabled a range of electrochemical applications. Standard synthesis protocols for manufacturing graphene aerogels require the use of sol-gel chemical reactions that are maintained at high temperatures for long periods of time ranging from 12 hours to several days. Here we report an ultrafast, acid-catalyzed sol-gel formation process in acetonitrile in which wet GO-loaded gels are realized within 2 hours at temperatures below 45°C. Spectroscopic and electrochemical analysis following supercritical drying and pyrolysis confirms the reduction of the GO in the aerogels to sp 2 carbon crystallites with no residual carbon-nitrogen bonds from the acetonitrile or its derivatives. This rapid synthesis M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 2 enhances the prospects for large-scale manufacturing of graphene aerogels for use in numerous applications including sorbents for environmental toxins, support materials for electrocatalysis, and high-performance electrodes for electrochemical capacitors and solar cells.

Preparation and Characterization of Graphene Oxide Aerogels: Exploring the Limits of Supercritical CO2 Fabrication Methods

“…690 m 2 g À1 and low density of 5 10 À2 gcm À3 ,a no utstanding mechanicalp erformance was reported, with up to 20 MPa Young's modulus. [6] In order to further evaluatet he structurali ntegrity of GO aerogels, fatigue tests with compressives train of 10 %f or 20 000 cycles were performed on GOa_333and GOaT_573 samples (Figure 7b). Concerning the fatigue behavior,b oth aerogels maintain their mechanical integrity, even after 20 000 cycles.…”

“…The high stabilityo fG Od ispersions in water is the starting keyp oint exploitedf or thef ormationo fr GO hydrogels by self-assembly underh ydrothermal conditions. [3][4][5][6][7] Those hydrogels must be furtherd ried, avoidingt he collapse of the porous structure, in order to obtain 3D aerogels with a sponge-like configuration. In contrast to graphene aerogels, the properties of 3D GO structures have been scarcely studied, due to the high chemical instability and poor mechanical properties of these networks.…”

Photothermal effects during nanodiamond synthesis from a carbon aerogel in a laser-heated diamond anvil cell

“…% Macron Fine Chemicals) [20]. The final molar ratios of acetonitrile, formaldehyde, and HCl relative to resorcinol were 100:1, 2:1, and 1:10, respectively [31,32]. This solution was quickly placed into a Branson 1510R-DTH ultrasonic cleaner for 30 minutes, and then removed and allowed to gel for about 24 hours, during which the gel turned light pink.…”

Carbon aerogel evolution: Allotrope, graphene-inspired, and 3D-printed aerogels

“…From here the strategy is similar to that used by Lim et al for fast sol-gel synthesis of GAs. 75 The nanodiamonds are suspended in acetonitrile, and gelation is achieved with the addition of RF and the acid catalyst. Final aerogels consist of nanodiamonds cross-linked with RF with surface areas greater than 500 m 2 /g.…”

“…74 Electrical conductivities for this covalently bonded GA were as high as 1 S/cm and surface areas ranged from 500 to 1200 m 2 /g. Lim et al 75 drastically reduced the time for GA synthesis using the RF cross-linking strategy by adapting the fast gelation method developed by Mulik et al 76 The fast gelation method uses a one-pot synthesis route to prepare GO-RF gels in just a few hours instead of days. First, GO is suspended in acetonitrile, instead of water, via sonication.…”