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Previous issue date: 2016-07-27 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Este trabalho teve como objetivo sintetizar o eletrodo Ti/TiO2-nanotubos/PbO2 por anodiza??o eletroqu?mica e eletrodeposi??o, investigar a produ??o de esp?cies oxidantes fortes e degrada??o eletroqu?mica do corante t?xtil sint?tico Vermelho ?cido 1. Para tanto, os nanotubos de TiO2 foram produzidos por anodiza??o eletroqu?mica em eletr?lito misto org?nico-inorg?nico, calcinados e, ent?o, decorados com PbO2 por eletrodeposi??o. Os nanotubos de TiO2 decorados com PbO2 foram caracterizados pelas t?cnicas de Microscopia Eletr?nica de Varredura, Difra??o de Raios X e por medidas potenciodin?micas. A determina??o de esp?cies oxidantes fortes foi realizada pelo m?todo ISCO (persulfato) e rea??o de aprisionamento de spin por RNO (radical hidroxila). A eletr?lise galvanost?tica da amostra sint?tica contendo o corante AR1 nos ?nodos Ti/Pt e Ti/TiO2-nanotubos/PbO2 foi monitorada por espectrometria de UV-vis?vel e demanda qu?mica de oxig?nio. Foi verificado que o eletrodo Ti/TiO2-nanotubos/PbO2 tem alto sobrepotencial para a rea??o de evolu??o de oxig?nio sendo um eletrocatalisador ruim para essa rea??o. Al?m disso, uma produ??o significante de radicais hidroxila e persulfato ? alcan?ada em Ti/TiO2-nanotubos/PbO2 quando comparado a Ti/Pt principalmente em densidade de corrente de 60 mA cm-2. Ele tamb?m mostrou melhor desempenho na remo??o do AR1 com descolora??o total do mesmo em 90 min e decaimento da demanda qu?mica de oxig?nio em 64% na densidade de 60 mA cm-2 e maior efici?ncia energ?tica em ambas as densidades de corrente de 7,5 e 60 mA cm-2 frente o eletrodo de Ti/Pt. Portanto, o eletrodo de Ti/TiO2-nanotubos/PbO2 exibe boas propriedades catal?ticas para aplica??es ambientais, tal como oxida??o an?dica. Al?m disso, a concentra??o dos oxidantes foi dependente do material do eletrodo e das condi??es de oxida??o an?dica. / This study aimed to synthesize the Ti/TiO2-nanotube/PbO2 electrode by anodizing electrochemistry and electroplating, investigate the production of strong oxidizing species and electrochemical degradation of synthetic textile dye Acid Red 1. Therefore, the TiO2 nanotubes were produced by anodizing electrochemistry in organic-inorganic mixed electrolyte, calcined and then decorated with PbO2 by electrodeposition. TiO2 nanotubes decorated with PbO2 were characterized by electron microscopy Scan, X-Ray Diffraction techniques and potentiodynamic measurements. The determination of strong oxidizing species was performed by ISCO method (persulfate) and spin trapping reaction by RNO (hydroxyl radical). The galvanostatic electrolysis of synthetic sample containing the dye AR1 in anodes Ti/Pt and Ti/TiO2-nanotube/PbO2 was monitored by UV-visible spectrometry and chemical oxygen demand. It was found that the Ti/TiO2-nanotube/PbO2 electrode has a high overpotential for the reaction of oxygen evolution is a bad electrocatalyst for this reaction. Furthermore, a significant production of hydroxyl radicals and persulfate is achieved in Ti/TiO2-nanotube/PbO2 compared to Ti/Pt mainly current density of 60 mA cm-2. It also showed better performance in the removal of AR1 complete discoloration with the same 90 min and decay of chemical oxygen demand by 64% the density of 60 mA cm-2 and greater efficiency in both current densities of 7.5 and 60 mA cm-2 across the electrode Ti/Pt. Therefore, the electrode Ti/TiO2-nanotube/PbO2 exhibits good catalytic properties for environmental applications, such as anodic oxidation. Furthermore, the concentration of the oxidizing electrode was dependent on the material and the anodic oxidation conditions.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/21971 |
| Date | 27 July 2016 |
| Creators | Santos, Jos? Eudes Lima |
| Contributors | 01139059980, Pergher, Sibele Berenice Castella, 50942611004, Braga, Tiago Pinheiro, 00880643366, Moura, Dayanne Chianca de, 04719087469, Santana, Renato Alexandre Costa de, 86688626420, Lima, Andressa Mota, Huitle, Carlos Alberto Martinez |
| Publisher | PROGRAMA DE P?S-GRADUA??O EM QU?MICA, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| 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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