Temperature effects on the oscillatory electro-oxidation of methanol on platinum

Autor(es)

Carbonio, Emilia A. ^[1] ; Nagao, Raphael ^[1] ; Gonzalez, Ernesto R. ^[1] ; Varela, Hamilton ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Quim Sao Carlos, BR-13560970 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Physical Chemistry Chemical Physics; v. 11, n. 4, p. 665-670, 2009.
• Citações Web of Science: 30

Resumo

We report in this paper the effect of temperature on the oscillatory electro-oxidation of methanol on polycrystalline platinum in aqueous sulfuric acid media. Potential oscillations were studied under galvanostatic control and at four temperatures ranging from 5 to 35 degrees C. For a given temperature, the departure from thermodynamic equilibrium does not affect the oscillation period and results in a slight increase of the oscillation amplitude. Apparent activation energies were also evaluated in voltammetric and chronoamperometric experiments and were compared to those obtained under oscillatory conditions. In any case, the apparent activation energies values fell into the region between 50 and 70 kJ mol(-1). Specifically under oscillatory conditions an apparent activation energy of 60 +/- 3 kJ mol(-1) and a temperature coefficient q(10) of about 2.3 were observed. The present findings extend our recently published report (J. Phys. Chem. A, 2008, 112, 4617) on the temperature effect on the oscillatory electro-oxidation of formic acid. We found that, despite the fact that both studies were carried out under similar conditions, unlike the case of formic acid, only conventional, Arrhenius, dynamics was observed for methanol. (AU)

• Processo FAPESP: 04/04528-0 - Auto-organização dinâmica na interface sólido-líquido
• Beneficiário: Hamilton Brandão Varela de Albuquerque
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores
• Processo FAPESP: 06/04636-3 - Auto-organização espaço-temporal na interface sólido/líquido: eletrooxidação de ácido fórmico sobre platina
• Beneficiário: Raphael Nagao de Sousa
• Modalidade de apoio: Bolsas no Brasil - Mestrado