Intercalation of Gas Molecules in Graphene Oxide Interlayer: The Role of Water

Abstract

Intercalation phenomena of gas molecules in the interlayer of graphene oxide have been investigated using CO2, CH4, H2, and N2 gases. Intercalation of gas molecules is highly affected by the affinity between the hydrophilic surface of GO and target molecules. Among tested gases, CO2 can only be intercalated. Furthermore, the swelling of interlayer changed the intercalation phenomena. Amounts of intercalated gases are significantly enhanced, and all the gases can be intercalated by retarded dynamics of intercalated water.

Sonication-free dispersion of large-area graphene oxide sheets using internal pressure from release of intercalated carbon dioxide

“…When CO 2 gas was injected in the water-swollen GO sheets at 5 bar, followed by freezing at À30°C, the interlayer of GO sheets decreased to 9.9 Å (2h: 8.9°, green line). This was because part of the space occupied by water molecules in the GO interlayer, was compressed by the force of the restructuring of the excess water molecules surrounding the GO sheet into ice [22,23]. The crystallization of water molecules into hexagonal ice was confirmed by several peaks (23.1, 24.6, 26.2, 34 and 40.4; green dots) in the CO 2 intercalated GO after freezing (Fig.…”

“…It is important to note that we chose CO 2 gas as the intercalating gas molecule for this study, because CO 2 gas molecules have strong tendency to be intercalated in water-swollen interlayer GO. This is because pre-intercalated water molecules in GO interlayer exhibit strongly reduced dynamic and dielectric constant due to the strong interaction of water with hydrophilic GO basal plane, which leads to the considerable gas storage in water-swollen GO, especially for CO 2 [22,23]. The stored CO 2 molecules were then locked in the interlayers by freezing (at À30°C) the excess water outside the interlayer, thus blocking access to the GO interlayers (Fig.…”

“…It is interesting that the amount of CO 2 stored within the water-swollen GO sheets (red dots) was almost twice that of the dried GO over the entire range of injection pressures (5-20 bar). This was due to the high affinity of CO 2 molecules for pre-intercalated water [22,23].…”

Recent developments in membranes for efficient hydrogen purification

“…However, the role of water was not intensively studied. Recently, Kim et al investigated the effects of water on the intercalation of gas molecules on graphene oxide interlayers [98]. The results revealed that the degree of intercalation was strongly influenced by the interaction between gas molecules and hydrophilic surface of graphene oxide, and only CO 2 could be intercalated in the dried interlayer of graphene oxide.…”

Graphene Oxides in Filtration and Separation Applications

“…All of the tested gases could then be intercalated, but the CO 2 could be mostly solvated, surrounded by the intercalated water molecules and partially with functional groups on GO surfaces. Moreover, because the interaction between the intercalated water and GO retards the dynamics of water molecules, enhanced gas storage could be achieved within the intercalated water [ 50 ].…”