Estudo computacional de folhas de óxido de grafeno com variados graus de oxidação

Abstract

Graphene and graphene oxide (GO) are materials that show important electronic properties for many applications, for example, in electrochemical, optical, and electronic devices. Although graphene is a difficult to synthesize, GO is, on the other hand, a fairly easy one, and it is possible to obtain graphene starting from GO. Graphene flakes with hydroxyl and epoxy functional groups were analyzed using quantum chemical methods (specifically, density functional theory). Also, the connections between the simulated 13C nuclear magnetic resonance (NMR) spectra and the structure of the system were searched. The study showed that the presence of the functional groups: (i) influences the emergence of peaks between 90 and 60 ppm in the NMR spectrum; (ii) shifts sp2 carbon peaks to the left of the NMR spectrum (increasing the average chemical shifts); (iii) and promotes the unification of 3 peaks in the sp2 carbon range that initially existed without the presence of the functional groups. It is shown that the obtained computational results have a good agreement with the NMR spectral changes observed in experiments of thermal reduction of GO