Síntese, caracterização e avaliação do sistema de Perovskitas Lamelares do tipo KSr2Nb(3-x)TaxO10 (X= 0, 1 e 2) como fotocatalisadores

Abstract

Niobates, tantalates and tantaloniobates in lamellar perovskite structures have a great influence in the literature, as they have several applications, among them, they stand out in photocatalytic processes. Understanding the influence of structural and electronic changes is a significant challenge in developing new materials. The cations Nb(V) and Ta(V) are relevant in this work because they have similar sonic rays in several coordinations. As a result, this work seeks to synthesize, characterize and evaluate the mixed oxides KSr2Nb3-xTaxO10 (x= 0 to 2), and subject them to photocatalytic tests in an occurrence model with Remazol Yellow Gold (RNL). The materials obtained were characterized by X-ray Diffraction (XRD) with Rietveld refinement, Vibrational Spectroscopy in the Infrared Region (IR), RAMAN Spectroscopy, elemental analysis by X-ray Fluorescence (EDS). Through refinement, Rietveld realized that the pure phases of the materials were not achieved, especially as Ta(V) enters the network, thus demonstrating the difficulty of preparing solid solutions. The IR spectra confirm the expected vibrations in the structures. The theoretical and experimental Ramans corroborate each other. EDX confirms the desired stoichiometric ratio. The photocatalytic results show that as tantalum is inserted into the network the percentages of discoloration are increased, this fact may be related to intraoctahedral distortions and the presence of different metals in the center of the octahedron.