Unravelling Some of the Structure–Property Relationships in Graphene Oxide at Low Degree of Oxidation

Abstract

Graphene oxide (GO) is a versatile 2D material whose properties can be tuned by changing the type and concentration of oxygen-containing functional groups attached to its surface. However, a detailed knowledge of the dependence of the chemo/physical features of this material on its chemical composition is largely unknown. We combine classical molecular dynamics and density functional theory simulations to predict the structural and electronic properties of GO at low degree of oxidation and suggest a revision of the Lerf-Klinowski model. We find that layer deformation is larger for samples containing high concentrations of epoxy groups and that correspondingly the band gap increases. Targeted chemical modification of the GO surface appears to be an effective route to tailor the electronic properties of the monolayer for given applications. Our simulations also show that the chemical shift of the C-1s XPS peak allows one to unambiguously characterize GO composition, resolving the peak attribution uncertainty often encountered in experiments.

A review on graphene based transition metal oxide composites and its application towards supercapacitor electrodes

“…Due to these fascinating properties, saturated absorption takes place when once optical intensity approaches a certain critical point [33]. Graphene can be functionalized which result various substances such as graphene oxide or fluorinated graphene [34]. At present, overwhelming attention has started to the electronic and framework features of carbon-based materials as well as graphene are now hottest topic in condensed matter physics.…”

Structure and synthesis of graphene oxide

“…On the detailed structure of GO, however, it remains some ambiguous and literature reports are still in argument ( Fig.1). [11,13,[15][16][17][18][19][20][21][22][23] In addition, methods in regard to synthesis of GO has been massively researched in the past few years. The effectiveness and environmental benignity was core driven force for the continuous evolvement.…”

Toward Large-Scale Production of Oxidized Graphene

“…After reduction, the prominent peaks in the GO spectrum result are significantly attenuated and weakened in the rGO spectrum, confirming the removal of The oxygen-containing functional groups are confirmed in the FTIR spectra given in Figure 3b. As is well-known, the hydroxyl and epoxide groups attached to the basal plane of the graphene and carboxyl and carbonyl groups located at the edges are the dominant functional groups [24]. The following characteristic functional groups are detected: C−O−C (1044 cm −1 ), C−O (1222 cm −1 ), C=C (1644 cm −1 ), and C=O (1729 cm −1 ).…”

“…To date, the basic structure of GO remains ambiguous due to the vast number of functional groups and the entailed isomeric possibilities. It is well-known that, depending on the degree of oxidation, the aromatic lattice of graphene exhibits different oxygen functional groups, such as hydroxyl, epoxy, carboxyl, and carbonyl groups [22][23][24], which increase the interlayer spacing from 0.33 nm (graphite) to 0.87 nm (GO) [25]. At a low degree of oxidation, hydroxyl groups can chemically turn into epoxide groups and vice versa, allowing for the use of GO for specific technological applications [24].…”

“…It is well-known that, depending on the degree of oxidation, the aromatic lattice of graphene exhibits different oxygen functional groups, such as hydroxyl, epoxy, carboxyl, and carbonyl groups [22][23][24], which increase the interlayer spacing from 0.33 nm (graphite) to 0.87 nm (GO) [25]. At a low degree of oxidation, hydroxyl groups can chemically turn into epoxide groups and vice versa, allowing for the use of GO for specific technological applications [24]. In addition, the GO structure reveals a mixed sp 2 −sp 3 hybridization as a direct consequence of the degree of oxidation acquired during the oxidation process [26] (see, e.g., Brodie [27], Staudenmaier [28], Hummer [29], Marcano [30], and Chen [31]).…”