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Previous issue date: 2016-08-05 / Foram sintetizadas nanoestruturas de ZnO:Ag com nanopart?culas (NPs) de prata a 100 ?C atrav?s de energia micro-ondas com o objetivo de obter um material com propriedades fotocatal?ticas (self-cleaning) em baixos n?veis de energia e magn?ticas. As aplica??es pr?ticas do nanomagnetismo s?o diversas que v?o da geologia, da grava??o magn?tica, at? a medicina. Desse modo, o material foi obtido a partir dos precursores: acetato de zinco di-hidratado e nitrato de prata em diferentes concentra??es tais como ZnO1-x:Agx (x= 0, 0.01 e 0.02). Adicionando a s?ntese polivinilpirrolidona (como agente surfactante) e hexametilenotetramina como agente redutor/agente de precipita??o. Para sua caracteriza??o foram realizadas Difra??es de Raios-X (DRX), Microscopia Eletr?nica de Varredura e por Efeito de Campo (MEV/FEG), Microscopia Eletr?nica de Transmiss?o (TEM), an?lises de ?rea de espec?fica por isortermas Brunauer, Emmett e Taller (BET), Fotoluminesc?ncia (PL) e Espectrofotometria. Os resultados de DRX apontaram principalmente fases cristalinas de Wurtzita para o ZnO e c?bica de face centrada para nanopart?culas de prata met?lica. Atrav?s da espectrofotometria foi poss?vel confirmar por absorb?ncia no comprimento de onda do corante alaranjado de metila a fotocat?lise do ZnO dopado com 1 mol% de prata, sintetizado em 10 min no tempo m?dio de 2 horas e 30 min. Por transmit?ncia foi obtido o gap direto e indireto das composi??es estudadas. Todas as composi??es obtidas apresentaram a propriedade de fotoluminesc?ncia gerada por defeitos estruturais. A dopagem ocasionou para o material puro um deslocamento do verde para o amarelo e o vermelho em consequ?ncia da diminui??o do gap. Apresentou tamb?m pico referente ?s nanopart?culas met?licas de prata em torno de 390 nm. As propriedades magn?ticas foram investigadas atrav?s da an?lise das curvas de magnetiza??o em temperaturas espec?ficas e da magnetiza??o em fun??o da temperatura, obtidas utilizando-se um sistema PPMS. Com estes resultados, foi realizada a etapa de impregna??o das nanopart?culas em poliamida pelo m?todo de deposi??o por imers?o, para isso foi utilizado estireno e acrilato de butila. A caracteriza??o do nanorevestimento foi realizada atrav?s das an?lises de DRX, MEV/EDS, an?lise t?rmica (TG/DTA), Espectroscopia no Infravermelho com Transformada de Fourier (FTIR), Microscopia de For?a At?mica (AFM) e ?ngulo de contato. A avalia??o da propriedade self-cleaning foi baseada na altera??o da cor (?E) usando o espectrofot?metro por reflect?ncia. / ZnO:Ag/Ag nanostructures were synthesized at 100 ?C by microwave energy in order to obtain a material with photocatalytic properties on low energy levels and magnetics. The applications of nanomagnetism are diverse ranging from geology, magnetic recording, to medicine. Thus, the material was obtained from the precursors: zinc acetate dihydrate and silver nitrate (as dopant) in different concentrations such as ZnO1-x:Agx (x= 0, 0.01 e 0.02). Adding polyvinylpyrrolidone synthesis (as surfactant) and hexamethylene as a reducing agent/precipitating agent. For its characterization, the following techniques were performed to evaluate, Diffraction of X-Rays (XRD), Scanning Electron Microscopy and Field Effect (SEM/FEG), Transmission Electron Microscopy (TEM), analysis by isotherms Brunauer surface area Emmett and Taller (BET), Photoluminescence (PL) and Spectrophotometry. The XRD results indicated mainly crystalline phases of wurtzite ZnO for the and for face-centered cubic metallic silver nanoparticles. By undertaking spectrophotometric absorbance it was confirmed by the orange color wavelength methyl photocatalysis ZnO doped with 1 mol% silver synthesized in 10 minutes in an average time of 2 hours and 30 min. Transmittance was obtained with direct and indirect gap of the compositions. All powders obtained showed the photoluminescence property generated by structural defects. The doping of the pure material caused a shift from green to between yellow and red, thus confirming changes in the electrical properties of the same due to decrease in the gap and also showed peak regarding the metal nanoparticles silver around 390 nm. The magnetic properties of the samples were performed using the physical property measurement system (PPMS) from Quantum. Under these conditions the doping improved the photocatalytic property of ZnO. With these prior results, to prove this application the impregnation step was carried out with particles of polyamide by immersion deposition method (dip coating), for this a styrene and butyl acrylate was utilised. The characterization of nano coating ware used using the following techniques: XRD, SEM/EDS, thermal analysis (TG/DTA), Infrared Spectroscopy Fourier Transform (FTIR), atomic force microscopy (AFM) and contact angle. For evaluation of the self-cleaning for photocatalysis property was based on the color change (?E) using the spectrophotometer by reflectance before and after subjecting the samples to ultraviolet radiation for anthocyanins.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/23643 |
| Date | 05 August 2016 |
| Creators | Souza, Renata Priscilla de Ara?jo |
| Contributors | 06296687877, http://lattes.cnpq.br/2365059843175411, Bohn, Felipe, 99793628049, http://lattes.cnpq.br/9522788035526763, Borges, Filipe Martel de Magalh?es, 83724427468, http://lattes.cnpq.br/3125652251177322, Nascimento, Jos? Heriberto Oliveira do, 02452573493, http://lattes.cnpq.br/7033735079037677, Godinho J?nior, M?rio, 17876195830, http://lattes.cnpq.br/8364676654739392, Melo, Maxymme Mendes de, 00846136457, http://lattes.cnpq.br/3779445657082353, Motta, Fabiana Villela da, Paskocimas, Carlos Alberto |
| Publisher | PROGRAMA DE P?S-GRADUA??O EM CI?NCIA E ENGENHARIA DE MATERIAIS, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| 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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