Obtenção via método hidrotérmico de micro-ondas e caracterização de nanopartículas de CeO2 e de seus nanocompósitos com nanotubos de carbono

Abstract

This work presented the synthesis of cerium oxide nanostructures (CeO2) and CeO2 nanocomposites with carbon nanotubes (NTC) by microwave hydrothermal method, considered efficient and profitable in obtaining the materials under study. The cerium oxide nanoparticles were obtained from the alkalinization of a solution of a cerium precursor salt and the nanocomposites were obtained under the mild conditions of microwave hydrothermal heating at 100 °C for 4 minutes with the addition of the carbon nanotubes. The synthesized materials were structurally characterized by X-ray diffraction (XRD), whose diffractograms showed a high degree of crystallinity for the samples of cerium oxide and CeO2/NTC nanocomposite with 0.15 mg of NTC and a high degree of purity in the three materials, since no peaks indicating the formation of secondary phases were observed; and by Raman spectroscopy, whose spectra showed the vibrational bands of Ce-O and NTC present in the nanocomposites, indicating short-range structural disorder with the addition of the carbon nanotubes in the oxide network. Morphologically, the synthesized materials were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), whose images illustrated the nanometric size of the cerium oxide particles, between 50 and 100 nm, and the way in which they are arranged by the carbon nanotube structures and verified that the presence of the nanotubes changes the shape and size of the cerium oxide nanoparticles. Therefore, from the structural characterizations it was possible to observe the formation of the cubic phase of the cerium oxide, evidencing the obtainment of materials with a high degree of crystallinity and the growth of the oxide nanoparticles on the walls of the carbon nanotubes, showing the efficiency of the microwave hydrothermal method to obtain the desired materials. The morphological characterizations showed the organization of the cerium oxide nanoparticle aggregates and the interaction of the NTCs when added to the oxide network, influencing the morphology of the material.