Preparation of cellulose–graphene oxide aerogels with N‐methyl morpholine‐N‐oxide as a solvent

Abstract

Cellulose-graphene oxide (GO) aerogel composites were successfully prepared from cellulose and GO dispersed in Nmethyl morpholine-N-oxide monohydrate, a nontoxic and environmentally friendly solvent, after a freeze-drying process. Because of the strong interactions between the numerous oxygen-containing groups located on the surface of GO and the functional groups of the cellulose molecules, the GO monolayers were well dispersed in the three-dimensional porous structure of the cellulose aerogels. With the addition of 10 wt % GO, the swelling ratios and water contents of the composite cellulose-GO aerogels increased from 468 to 706% and from 82.4% to 87.6%, respectively. The corresponding maximum decomposition temperatures also increased from 335 to 353 8C with increasing GO content from 0 to 10%; this indicated that the thermal stability of the cellulose-GO aerogels was enhanced.

Effects of Sodium Montmorillonite on the Preparation and Properties of Cellulose Aerogels

“…Simultaneously, a large amount of particulate matter was attached to the pore wall of the cellulose/montmorillonite aerogel, and the EDS spectrum (Figure 4) showed that the elemental composition consisted of Na, Mg, Al and Si. Furthermore, the average pore size decreased from 87.3–370 μm range for pure cellulose aerogel to the 295 nm–6.75 µm range for 3-wt % cellulose/montmorillonite aerogel, which was similar to the aerogel pore size reported by Zhou et al [28]. The results of the N 2 adsorption experiment showed that the specific surface area increased from 7.79 m 2 /g to 23.18 m 2 /g.…”

Cellulose Aerogels: Synthesis, Applications, and Prospects

“…In addition, Fu et al found that the silica particles attached to the nanocellulosic scaffold could promote the thermal stability of the cellulose matrix [197]. GO can also enhance the thermal stabilities of cellulose, because of the formation of an extensive H-bonded network between the GO and the cellulose [198]. However, as the content of SiO 2 increases, the specific surface area and density of the aerogels increase, and the aerogels may even rupture.…”

GO Wrapping Yolk‐Shell S/MnO2 Nanocomposites as High Performance Cathode for Lithium/Sulfur Cells

“…The XRD pattern (Figure e) shows the obtained sample is composed of sulfur [JCPDS#08‐0247] and Birnessite‐type MnO 2 (δ‐MnO 2 ) [JCPDS#80‐1098]. The characteristic diffraction peak of GO is located at around 2θ=12°, close to one characteristic peak of S. Therefore the Raman spectrum is employed to further investigate the existence of sulfur and GO in the S/MnO 2 /GO nanocomposite (Figure f). The characteristic Raman peaks of the S/MnO 2 /GO composite are coincident with the pure S at 156, 222, 475 cm −1 , indicating the existence of S in the composite.…”

“…[31] Figure 4a illustrates the driven force of the assembly process of the GO 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 layer, which could be mainly ascribed to two: (i) hydrogen bonding between groups of amino and hydroxyl in chitosan (CS) chains and oxygen-containing functional groups on GO sheets, and (ii) electrostatic interaction between positively charged CS chains and negatively charged GO sheets. [32,33] The S/MnO 2 nanocomposite is tightly encapsulated into the GO network as presented in Figure 4b The characteristic diffraction peak of GO is located at around 2θ = 12°, [34] close to one characteristic peak of S. Therefore the Raman spectrum is employed to further investigate the existence of sulfur and GO in the S/MnO 2 /GO nanocomposite ( and 1.95 V for the S/MnO 2 sample, while at about 2.27 and 1.97 V for the S/MnO 2 /GO electrode. Those two typical reduction peaks could be ascribed to the multistep reduction mechanism of element sulfur.…”