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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Oscillatory Electro-oxidation of Methanol on Nanoarchitectured Pt-pc/Rh/Pt Metallic Multilayer

Texto completo
Autor(es):
Nagao, Raphael [1, 2] ; Freitas, Renato G. [2, 3] ; Silva, Camila D. [2] ; Varela, Hamilton [1, 4] ; Pereira, Ernesto C. [2]
Número total de Autores: 5
Afiliação do(s) autor(es):
[1] Univ Sao Paulo, Inst Chem Sao Carlos, BR-13560970 Sao Paulo - Brazil
[2] Univ Fed Sao Carlos, Dept Chem, BR-13565905 Sao Paulo - Brazil
[3] Univ Fed Mato Grosso, Dept Chem, BR-78060900 Cuiaba, Mato Grosso - Brazil
[4] GIST, Ertl Ctr Electrochem & Catalysis, Kwangju 500712 - South Korea
Número total de Afiliações: 4
Tipo de documento: Artigo Científico
Fonte: ACS CATALYSIS; v. 5, n. 2, p. 1045-1052, FEB 2015.
Citações Web of Science: 7
Resumo

The oscillatory electro-oxidation of methanol was studied on polycrystalline Pt-pc and Pt-pc/Rh-2.0/Pt-1.0 metallic multilayers. The surfaces investigated consisted of 1.0 Pt outlayer surface deposited onto 2.0 Rh intralayers beneath a Pt outlayer and over the polycrystalline Pt-pc, substrate. In addition to experimental studies, numerical simulations were performed using a dimensionless kinetic model for the electro-oxidation of methanol in order to provide a better understanding of the role 0 played by the nanostructured metallic multilayer electrode in the electrocatalytic activity. A comparable electrochemical behavior found for cyclic voltammetry in blank acidic media was observed in both electrodes. Remarkably, an increase of 90% in the peak current density around 0.88 V vs. RHE in the electro-oxidation of methanol appeared when Pt-pc/Rh-2.0/Pt-1.0 was utilized. The numerical simulations suggested that this increase in the electrocatalytic activity for the metallic multilayer electrode is due to the prevention of carbon monoxide adsorption on the surface and a consequent increase in the production of carbon dioxide from the direct pathway. Indeed, a decrease in the reaction rate constant of carbon monoxide formation resulted in an increase of the current density associated with CO2 formation in the potentiodynamic sweep, in addition to the decrease in amplitude and frequency of the oscillatory time series. As the rate of carbon monoxide adsorption is suppressed by the presence of the metallic multilayers, the intrinsic drift usually found in the oscillatory electro-oxidation of methanol was enhanced and oscillations ceased earlier. Overall, the combination of electrochemical experiments and numerical simulations suggests that carbon monoxide acts as a poisoning species instead of a reaction intermediate in the electro-oxidation of methanol. (AU)

Processo FAPESP: 13/16930-7 - Eletrocatálise V: processos eletrocatalíticos de interconversão entre as energias química e elétrica
Beneficiário:Edson Antonio Ticianelli
Modalidade de apoio: Auxílio à Pesquisa - Temático
Processo FAPESP: 10/05555-2 - Investigação da formação eletroquímica de nanotubos-TiO2 e sua aplicação em sistemas conversores de energia nanoarquiteturados
Beneficiário:Renato Garcia de Freitas Sobrinho
Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
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