Estudo computacional da interação do grafeno com gases do efeito estufa.

Abstract

Among the different gas sensors based on semiconductors, graphene is a semiconductor material that stands out on this subject, due to its precision in detecting a variety of gases. Doping in graphene with other elements can alter the properties of graphene surfaces that are used as sensors for nitrogen-based greenhouse gases (NH3, NO, NO2 and N2O). In this context, the theoretical computational study, from the point of view of chemical bonding, helps to understand the behavior of acid-base pairs formed between surfaces of pure graphene and doped with nitrogen-based gases. In order to carry out this theoretical study, computational models of chemical bond analysis were performed, based on the density functional theory (Density Functional Theory - DFT), to obtain chemical bond properties. Boron, aluminum and gallium dopants were selected in order to form Lewis acid-base pairs with the gas molecules. The computational methodologies of chemical bond analysis used were: the quantum theory of atoms in molecules (Quantum Theory of Atoms in Molecules - QTAIM) and the chemical bond covering model (Chemical Bond Overlap Properties - OP). The properties obtained for the graphene-gas molecular systems vary according to the change in the dopants and the sizes of the graphene sheets. The interactions between graphene Al @ and B @ have been shown to be more efficient and have a higher selectivity with gases, compared to pure graphene sheet.