Caracterização física de óxidos de nióbio por difração de raios X, espectroscopia raman e uv-vis

Abstract

In recent years, materials containing niobium have been widely investigated by the scientific community, due to their physical properties that allow important applications in high-tech industries, especially in the aerospace and electronics sectors. In this scenario, niobium oxides add value to nanoscience and nanotechnology because they are presented in different stoichiometries, such as niobium monoxide (NbO), niobium dioxide (NbOβ), and niobium pentoxide (NbβO5). The latter is the most studied phase and is used in various applications, such as in electronic and optical materials, in catalysts, in the glass and ceramics industry, among others. The present work aims to perform the physical characterization of niobium oxides through X-ray diffraction, Raman and Ultraviolet-visible spectroscopy techniques, performed on a powder sample of the oxide. For X-ray diffraction, the following parameters were used: voltage of 45 KV, scanning in βθ from 6º to 90º and Cu-Kα radiation (λ = 1.54 Å). The Raman tests were performed with a laser line λ = 5γβ nm, covering the spectral range of 50 to 1100 cm-1, with resolution of β cm-1 and an excitation power of 1 mW. For UV-Vis analysis of the sample, a UV-β600 Ultraviolet Visible Spectrophotometer was used, with a scanning range of β00 to 800 nm and medium scanning speed. From the results obtained from XRD, Raman and UV-Vis, it was possible to characterize the niobium oxides and their different identified crystalline phases, determine the crystalline structures, the preferential orientation of the planes, measure the lattice parameters, analyze the symmetry and characteristic vibration modes, verify the absorbance, transmittance, reflectance and band gap of the studied system, characterizing the phase corresponding to the spectra obtained. The results were in agreement with those presented in the literature regarding the phases, with NbβO5 being the predominant phase in the sample, confirming its important optical properties and the characteristic vibration bands of its structure