Estrutura, espectro e síntese do óxido de grafeno do ponto de vista computacional

Abstract

It is easy to realize the attention that graphene has gained in the scientific community. This material has become the focus of several research groups because of their excellent physical properties and the fact that its surface and edges can be functionalized. In the search of graphene by chemical exfoliation of the graphite, the graphene oxide (GO) is an intermediate product which has drawn much attention by itself. The GO can be used not only in graphene synthesis, but also in other various direct technological applications. In this dissertation, we made discussion of how a finite and well known molecule, the coronene [C24H12] can be used to create a model to study the structural and spectroscopic changes generated by oxygenated groups on GO, producing a signature comparable with experimental data. Furthermore, the synthesis of GO is analyzed, suggesting a hypothetical reaction mechanism with a theoretical and experimental foundation, on which the sulfate ion is the oxidizing agent of the layers of graphite. To do this, structural otimizations and calculations of IR spectra (via AM1 and DFTB3LYP) and Raman (via DFT-B3LYP) were carried out. As results, we obtained data compatible with our experiments, and useful for the analysis of IR and Raman spectra of GO, with regard to facilitating the understanding and the assignment of commonly found peaks in experimental measurements and also more detailed information about the synthesis process of this material.