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Previous issue date: 2012-08-03 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Nanostructured materials have been spreading successfully over past years due its size
and unusual properties, resulting in an exponential growth of research activities devoted to
nanoscience and nanotechnology, which has stimulated the search for different methods to
control main properties of nanomaterials and make them suitable for applications with high
added value. In the late 90 s an alternative and low cost method was proposed from alkaline
hydrothermal synthesis of nanotubes. Based on this context, the objective of this work was to
prepare different materials based on TiO2 anatase using hydrothermal synthesis method
proposed by Kasuga and submit them to an acid wash treatment, in order to check the
structural behavior of final samples. They were characterized by X-ray diffraction (XRD),
scanning electron microscopy (SEM), transmission electron microscopy (TEM),
adsorption/desorption of N2, thermal analysis (TG/DTA) and various spectroscopic methods
such as absorption spectroscopy in the infrared (FT-IR), Raman spectroscopy and X-ray
photoelectron spectroscopy (XPS). All the information of characterizations confirmed the
complete conversion of anatase TiO2 in nanotubes titanates (TTNT). Observing the influence
of acid washing treatment in titanates structure, it was concluded that the nanotubes are
formed during heat treatment, the sample which was not subjected to this process also
achieved a complete phase transformation, as showed in crystallography and morphology
results, however the surface area of them practically doubled after the acid washing. By
spectroscopy was performed a discussion about chemical composition of these titanates,
obtaining relevant results. Finally, it was observed that the products obtained in this work are
potential materials for various applications in adsorption, catalysis and photocatalysis,
showing great promise in CO2 capture / Materiais nanoestruturados t?m se difundido com sucesso ao longo dos ?ltimos anos,
isso devido ao seu tamanho e propriedades incomuns, resultando em um crescimento
exponencial das atividades de investiga??o dedicadas ? nanoci?ncia e nanotecnologia, o que
tem estimulado a procura por diferentes m?todos que possam controlar as principais
propriedades dos nanomateriais a fim de adequ?-los para aplica??es de alto valor agregado.
No final da d?cada de 90 um m?todo alternativo e de baixo custo foi proposto a partir da
s?ntese hidrot?rmica alcalina de nanotubos. Baseando-se nesse contexto, o objetivo deste
trabalho foi preparar diferentes materiais ? base de TiO2 anatase utilizando o m?todo de
s?ntese hidrot?rmica proposto por Kasuga e submet?-los em seguida a um tratamento de
lavagem ?cida, com o prop?sito de verificar o comportamento estrutural das amostras finais.
Essas foram caracterizadas por difratometria de raios X (DRX), microscopia eletr?nica de
varredura (MEV), microscopia eletr?nica de transmiss?o (MET), adsor??o/dessor??o de N2,
an?lise t?rmica (ATG/ATD) e diferentes m?todos espectrosc?picos como, espectroscopia de
absor??o na regi?o do infravermelho (FT-IR), espectroscopia Raman e espectroscopia
fotoeletr?nica de raios X (XPS). O conjunto de caracteriza??es se complementou,
confirmando a transforma??o completa do TiO2 anatase de partida em titanatos nanotubulares
(TTNT). Ao observar a influ?ncia que o tratamento de lavagem ?cida exerce na estrutura do
mesmo, conclui-se que os nanotubos s?o formados durante o tratamento t?rmico, pois a
amostra que n?o foi submetida ao processo tamb?m alcan?ou uma transforma??o completa de
fase, conforme os resultados de cristalografia e morfologia, entretanto a ?rea espec?fica deles
? praticamente dobrada ap?s a lavagem ?cida. Por espectroscopia foi realizada uma minusiosa
discuss?o acerca da composi??o qu?mica desses titanatos, obtendo resultados relevantes. Por
fim, ressalta-se que os produtos obtidos nesse trabalho s?o materiais com potencial para
diferentes aplica??es em adsor??o, cat?lise e fotocat?lise, se mostrando promissores na
captura do CO2
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/17760 |
| Date | 03 August 2012 |
| Creators | Silva, Edjane Fabiula Buriti da |
| Contributors | CPF:35530502415, http://lattes.cnpq.br/9770622597949866, Guedes, Ana Paula de Melo Alves, CPF:03330987499, http://lattes.cnpq.br/5738717177200782, Gonzalez, Ernesto Antonio Urquieta, CPF:00085619825, http://lattes.cnpq.br/2389975677904655, Rubim, Joel Camargo, CPF:01045913820, http://lattes.cnpq.br/8243497871129180, Pergher, Sibele Berenice Castella, CPF:50942611004, http://lattes.cnpq.br/5249001430287414, Ara?jo, Ant?nio Souza de |
| Publisher | Universidade Federal do Rio Grande do Norte, Programa de P?s-Gradua??o em Qu?mica, UFRN, BR, F?sico-Qu?mica; Qu?mica |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Format | application/pdf |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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