Estudo teórico de nanotubos de dióxido de zircônio e suas interações com moléculas

Abstract

This research has as its main theme the study of zirconium dioxide nanotubes and their interactions with molecules. It is well known that since the discovery of carbon nanotubes in 1991 and inorganic nanotubes in 1992, significant interest has developed in the study of technological and scientific applications of these structures, causing a scientific interest in relating these new structural forms to properties. The substances formed by the group 4 elements of the periodic table, mainly titanium and zirconium, have numerous technological applications, such as the use of titanium in the construction of metal alloys, zirconium in the synthesis of ceramic materials and both in the construction of gas sensors.Among the substances formed by these elements, one of the least reported in the literature is zirconium dioxide nanotubes. In this sense, this work aims to study zirconium dioxide nanotubes and their interactions with molecules. For this theoretical study, single wall zirconium dioxide nanotube models were created using computational programs developed in the Shell Bash language of Linguux, considering the cubic morphology of the zirconium crystal from the crystalline planes (110) and (111). Nanotube models were also created considering the rutile shape from the crystalline plane (110).The properties of the modeled structures, such as stability, gap, dipole and state density as well as the simulation of the interactions of some of these structures with the molecules CO, CO2, O2, H2O and CH2O (metanal), N2, H2, CH4, NH3, C2H4O2 (etanoic acid) were obtained through mechanical calculations. quantum using the semi-empirical methods PM7 and ab initio B3LYP, with bases 3-21G and LANL2DZ. The nanotube geometries, after optimization, showed greater stability in relation to their original planes, and the models obtained from the crystalline plane (111) of the cubic morphology presented the greatest stability in relation to the other models. The outer surfaces of the nanotube models obtained are more reactive than the inner surfaces, with the polar molecules being the most reactive on both surfaces, with the acetic acid and water molecules being the most reactive.