Síntese, caracterização e avaliação eletroquímica de nanopartículas intermetálicas ordenadas PtSb e PtSn
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Data
2008-07-11
Autores
Silva, Marcelo Rodrigues da [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Nos últimos anos a questão energética tem sido o foco principal de grande parte da comunidade cientifica, onde a mesma se empenha arduamente na busca por soluções alternativas aos sobrecarregados meios convencionais de obtenção de energia elétrica. Neste contexto, as células a combustível surgem como sistemas alternativos na geração de energia elétrica. Tais dispositivos convertem energia química em energia elétrica de forma direta, silenciosa e, principalmente, ecologicamente correta. Dentre os vários tipos de células a combustível, as células PEMFC (Próton Exchange Membrane Fuel Cell) se destacam das demais, pois podem utilizar vários combustíveis em sua configuração, além de operar em baixas temperaturas, sendo ideais para sistemas portáteis, veiculares e estacionários. Neste sentido, o presente trabalho se apresenta de forma a desenvolver materiais com elevada eletroatividade para serem implantados no compartimento anódico destes sistemas. Dentre os inúmeros tipos de materiais que podem ser utilizados nesta configuração de célula, os compostos intermetálicos de fase ordenada surgem como excelente alternativa, pois os mesmos apresentam elevada eletroatividade frente à oxidação de hidrogênio e álcoois de baixo peso molecular. Os compostos intermetálicos nanoparticulados PtSn, PtSb, PtSn/C e PtSb/C e a Pt/C foram sintetizados em baixa temperatura via processo poliol utilizando etileno glicol como solvente e agente redutor, e carbono vulcan XC-72 como suporte. Os eletrocatalisadores obtidos foram caracterizados por Difração de Raios - X (DRX), Microscopia Eletrônica de Varredura (MEV), Microscopia Eletrônica de Transmissão (TEM) e Espectroscopia de Energia Dispersiva por Raios - X (EDX). A técnica DRX mostrou que o produto final é predominantemente composto pelas fases intermetálicas ordenadas, coexistindo...
In the last years the energy issue has been the main focus of much of the scientific community, where it strives hard in the search for alternative solutions to overburdened conventional ways of obtaining electric energy. In this context, fuel cells appear as alternative systems in the generation of electric energy. Such devices convert chemical energy into electrical energy in a direct, silent and mostly environmentally correct manner. Among the various configuration of fuel cells, the PEMFC (Proton Exchange Membrane Fuel Cell) one stand out from the others as they may fed by different fuels, operate at low temperatures and they are ideal for portable, veiculares and stationary uses. In this perspective, the present work present the results obtained from de search for electrode materials with high electroactivity to be implanted in the anodic compartment of PEMFC. Ordered intermetallics materials emerge as excellent electrode material, alternative to Platinum, and moreover they can be successfully used as methodological tool to understand electrocatalysis process. Furthermore, they exhibited high electroactivity toward the oxidation reaction of hydrogen and low molecular weight alcohols. The nanoparticles intermetallics compounds PtSn, PtSb, PtSn/C and PtSb/C and Pt/C were synthesized at low temperature by polyol process using ethylene glycol as a solvent and reducing agent, and carbon Vulcan XC-72 as support. The electrocatalysts were characterized by X-Ray Diffraction(XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscope (TEM) and Energy Dispersive X-ray Spectroscopy (EDX). XRD showed that the final product is predominantly composed by ordered intermetallics phases, coexisting a secondary phase of the platinum (cfc) in the materials PtSn/C, PtSb/C and PtSb... (Complete abstract click electronic access below)
In the last years the energy issue has been the main focus of much of the scientific community, where it strives hard in the search for alternative solutions to overburdened conventional ways of obtaining electric energy. In this context, fuel cells appear as alternative systems in the generation of electric energy. Such devices convert chemical energy into electrical energy in a direct, silent and mostly environmentally correct manner. Among the various configuration of fuel cells, the PEMFC (Proton Exchange Membrane Fuel Cell) one stand out from the others as they may fed by different fuels, operate at low temperatures and they are ideal for portable, veiculares and stationary uses. In this perspective, the present work present the results obtained from de search for electrode materials with high electroactivity to be implanted in the anodic compartment of PEMFC. Ordered intermetallics materials emerge as excellent electrode material, alternative to Platinum, and moreover they can be successfully used as methodological tool to understand electrocatalysis process. Furthermore, they exhibited high electroactivity toward the oxidation reaction of hydrogen and low molecular weight alcohols. The nanoparticles intermetallics compounds PtSn, PtSb, PtSn/C and PtSb/C and Pt/C were synthesized at low temperature by polyol process using ethylene glycol as a solvent and reducing agent, and carbon Vulcan XC-72 as support. The electrocatalysts were characterized by X-Ray Diffraction(XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscope (TEM) and Energy Dispersive X-ray Spectroscopy (EDX). XRD showed that the final product is predominantly composed by ordered intermetallics phases, coexisting a secondary phase of the platinum (cfc) in the materials PtSn/C, PtSb/C and PtSb... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Compostos intermetalicos, Célula a combustível, Nanopartículas, Fuel cell, Nanoparticles
Como citar
SILVA, Marcelo Rodrigues da. Síntese, caracterização e avaliação eletroquímica de nanopartículas intermetálicas ordenadas PtSb e PtSn. 2008. 135 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Ciências de Bauru, 2008.