The Role of Diamines in the Formation of Graphene Aerogels

Abstract

Aliphatic or aromatic diamines undergo nucleophilic attack on the epoxy groups of graphene oxide under hydrothermal conditions resulting in partial functionalization and partial reduction of the graphenic surface. The overall reaction decreases the solubility of graphene oxide and yields a hydrogel that can be dried to a 3D porous structure classified as an aerogel. This article compares the graphene aerogels derived from different aliphatic and aromatic diamines.

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“…These characteristics are probably related to the flexibility and the higher reactivity as nucleophile of the aliphatic amine, as reported in previous work. [14] Moreover, the thickness of electrode coating is approximately 750 μm, as estimated by cross-section SEM measurement (Figure 2e).…”

“…The same bands in GO appeared at 1366 and 1600 cm À 1 . [14] The G band appeared clearly asymmetric due to the contribution of D' band, while the D and G bands in CP-OPD -GA are contaminated by signals probably due to the presence of the aromatic diamine. The increase of the I D /I G ratio is usually attributed to the decrease of average size of sp 2 domains, together with an increase of the number of those domains after reduction.…”

“…The hydrogel in CP‐ TETA ‐GA was formed much earlier in contrast with that of CP‐ OPD ‐GA and showed better morphological characteristics such as homogeneous porosity, mechanical stability. These characteristics are probably related to the flexibility and the higher reactivity as nucleophile of the aliphatic amine, as reported in previous work . Moreover, the thickness of electrode coating is approximately 750 μm, as estimated by cross‐section SEM measurement (Figure e).…”

“…The XRD patterns of GO, Carbon Paper and CP‐GAs are presented in Figure a. GO shows an intense peak at 2θ=11.4°, which corresponds to an interlayer distance of 0.77 nm, due to absorbed water molecules between graphene layers and the existence of oxygen functional groups . The XRD patterns of CP‐GAs shows the same peaks with Carbon Paper and absence of any intense characteristic peak, which is an indication of the effective exfoliation of rGO nanosheets.…”

“…D (A 1g symmetry mode) and G (E 2g mode of the sp 2 carbon atoms) bands in the modified with diamines rGO aerogels appeared as well‐defined peaks at 1370 and 1582 cm −1 , respectively. The same bands in GO appeared at 1366 and 1600 cm −1 . The G band appeared clearly asymmetric due to the contribution of D’ band, while the D and G bands in CP‐ OPD ‐GA are contaminated by signals probably due to the presence of the aromatic diamine.…”