Obtenção e caracterização de nanoestruturas puras e dopadas a base de 'TI''O'IND.2' para a aplicação em fotocatálise

• Ano de defesa: 2014
• Autor(a) principal: Rodrigues, Daniela Cristina Manfroi [UNESP]
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual Paulista (Unesp)
• Palavras-chave em Português: Nanotubos; Titanato; Semicondutores dopados; Fotoluminescencia; Fotocatalise; Photocatalysis
• Link de acesso: http://hdl.handle.net/11449/124530

This work aims to obtain sodium titanate nanostructures (Na2Ti6O13), pure and doped, using the microwave assisted hydrothermal method, aiming photocatalytic application in rhodamine B dye discoloration. In hydrothermal synthesis process, parameters such power microwave irradiation (450W), volume (50 mL), TiO2 concentration (~ 0.5 g) and NaOH (10 M) were kept fixed. In the first stage of this study TiO2 (anatase) commercial was used as a precursor for nanotubes formation. In this step, the effects of temperature and reaction time in the product characteristics. The temperature range used for obtaining the nanotubes was 130 to 200 ° C while the reaction time varied from 0.5 to 4 hours. In all syntheses the product formed was sodium titanate (Na2Ti6O13) identified by the presence of peaks at 2θ equal to 10, 24, 28, 48 °, when analyzed by X-ray diffraction, XRD. For high-resolution electron microscopic analysis, SEM, it was observed that the morphology of 1D nanostructures, which by transmission microscopy images, MET, associated surface area analysis (BET), in the range 300-400 m2 g-1, be evidenced nanotubes. All samples prepared at this stage, were active in the rhodamine B discoloration, and that obtained at 130 ° C for 3 h and 180 ° C for 1 h were better. The optical characteristics of these samples showed emission in the visible region of the photoluminescence spectra, particularly in the blue (relative proportion of 3 to 7%) and also green emission that was greater than or equal to orange. The titanium isopropoxide was also used as a precursor, keeping all the conditions established at the first stage, obtaining samples with the same structural and optical profiles, which were also active for photocatalysis. The nanotubes obtained were modified with silver, which was added to the precursor solution synthesis (dopant) or after synthesis (surface modifier). It has been found that the presence ...