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Master's Dissertation
DOI
10.11606/D.75.2009.tde-13112009-100805
Document
Author
Full name
Luiz Felipe Nardin Barreta
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Carlos, 2009
Supervisor
Committee
Gonzalez, Ernesto Rafael (President)
Varanda, Laudemir Carlos
Vichi, Flavio Maron
Title in Portuguese
Estudo da reação de redução de oxigênio em meio ácido em eletrocatalisadores de platina e paládio dispersos em carbono
Keywords in Portuguese
paládio
platina
Redução de Oxigênio
Abstract in Portuguese
A Reação de Redução de Oxigênio (RRO) foi estudada em eletrocatalisadores constituídos por platina e paládio suportados em carbono em eletrólito de H2SO4. A caracterização estrutural foi realizada por DRX (difratometria de raios X) e a composição dos catalisadores foi determinada por EDX (espectroscopia de energia dispersiva de raios X). As propriedades eletrônicas foram investigadas por XAS (X-ray absorption spectroscopy) in situ, na região de XANES (X-ray absorption near edge structure). As atividades dos catalisadores foram comparadas por curvas de Tafel corrigidas por transporte de massa. Os materiais formados por Pt-Pd suportados em carbono mostraram maior atividade específica para a RRO quando comparados com os catalisadores constituídos somente por platina suportada em carbono. A maior atividade foi relacionada a uma menor força de adsorção de espécies oxigenadas nesses catalisadores.
Title in English
Study of oxygen reduction reaction in acidic media on platinum and palladium electrocatalysts supported on carbon
Keywords in English
Oxygen Reduction
palladium
platinum
Abstract in English
Oxygen reduction reaction (ORR) on platinum-palladium electrocatalysts supported on carbon was studied in H2SO4 electrolyte. The structure of the catalysts was characterized by XRD (X-ray diffractometry) and the composition was determined by EDX (Energy dispersive X-ray spectroscopy). The electronic properties were investigated by in situ XAS (X-ray absorption spectroscopy) in the XANES (X-ray absorption near edge structure) region. Mass-transport corrected Tafel plots were used to compare the electrocatalytic activity of the materials. The Pt-Pd catalysts have shown higher specific electrocatalytic activity than Pt only catalysts. The higher activity of Pt-Pd catalysts was attributed to a lower adsorption energy of oxygenated species in these catalysts.
 
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Publishing Date
2010-06-29
 
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