Formation and Decomposition of CO₂ Intercalated Graphene Oxide

Abstract

The formation, stability, and decomposition of CO2 intercalated graphene oxide was analyzed by FTIR, TGA-MS, TGA-IR, AFM, and SEM for the first time. We found that the formation starts at 50 °C and develops up to 120 °C. The formation process can be best observed by FTIR spectroscopy, and the product is stable at ambient conditions. At higher temperatures, the decomposition of CO2 intercalated graphene oxide occurs due to the release of water, CO2, and CO that can be monitored by TGA-MS and TGA-IR analysis. AFM and SEM images can visualize the formation of blisters in GO films that become instable at 210 °C. We further prepared graphene oxide with a low water-content and found that the formation of CO2 was significantly suppressed and CO became the major species responsible for the weight loss. In addition we prepared 18OH2 treated graphene oxide to elucidate the formation process of CO2 and found C16O18O by TGA-MS analysis that proves the crucial role of water during CO2 formation. From these experiments we propose that hydrate species are key-intermediates for the formation of CO2. Hence, it seems likely that rearrangement reactions that can proceed via hydrate intermediates, known from organic chemistry, are probably responsible for the formation of carboxylic acids at the edges of graphene oxide sheets after sonication of graphite oxide. Further, our investigations prove that graphene oxide is less stable than shown by TGA measurements. This has a high impact on the electronic properties of reduced graphene oxide, especially for all those using it for electronic applications.

High-yield preparation of graphene oxide from small graphite flakes via an improved Hummers method with a simple purification process

“…Thermalgravimetric analysis (TGA) curves of GO325 and GO1200 (Fig. 5b) exhibit similar characteristics: a weight loss before 100°C is resulted from the releasing of trapped water between GO sheets [27]; the sharp weight loss between 200 and 230°C is attributed to the decomposition of less stable oxygen containing functional groups on GO sheets [11]. A gradual mass loss in the range of 230-800°C is related to the removal of more stable functional groups.…”

“…The FTIR-ATR spectra of freeze-dried GO325 and GO1200 (Fig. 5c) show the following characteristic functional groups of GO [16,27]: CAOAC ($1000 cm À1 ), CAO (1230 cm À1 ), C@C ($1620 cm À1 ), and C@O (1740-1720 cm À1 ) bonds. The OAH stretching vibrations in the region of 3600-3300 cm À1 correspond to the hydroxyl and carboxyl groups of GO and residual water between GO sheets.…”

Thermal conductivity of epoxy adhesive enhanced by hybrid graphene oxide/AlN particles

“…In terms of as-prepared GO, the stretching vibrations of C@O from carbonyl and carboxylic are detected around 1725 cm À1 , C@C skeleton vibration absorption from unoxidized graphite at 1626 cm À1 [29]. Additionally, the absorption bands at 1384 cm À1 , 1200 cm À1 , 1049 cm À1 represent the O@H vibration absorption, epoxy groups C@O@C stretching vibration absorption and C@O stretching vibration absorption respectively [35], indicating the existence of hydroxyl, carboxyl, and epoxy group on the surface of GO.…”

Chemistry with Graphene and Graphene Oxide—Challenges for Synthetic Chemists

“…[115] In addition, 18 O from adsorbed 18 OH 2 is incorporated in the cleaved CO 2 , which is very likely due to the formation of hydrates from carbonyl groups of GO. [115] Figure 16. Selected reaction types for the functionalization of graphene and few-layer graphene.…”