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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.)

Borohydride Electrooxidation on Carbon-Supported Noble Metal Nanoparticles: Insights into Hydrogen and Hydroxyborane Formation

Texto completo
Autor(es):
Pasqualeti, Anielli M. [1] ; Olu, Pierre-Yves [2, 3] ; Chatenet, Marian [2, 3, 4] ; Lima, Fabio H. B. [1]
Número total de Autores: 4
Afiliação do(s) autor(es):
[1] Univ Sao Paulo, Inst Chem Sao Carlos, BR-13560970 Sao Paulo - Brazil
[2] Univ Grenoble Alpes, LEPMI, F-38000 Grenoble - France
[3] CNRS, LEPMI, F-38000 Grenoble - France
[4] French Univ Inst, F-75005 Paris - France
Número total de Afiliações: 4
Tipo de documento: Artigo Científico
Fonte: ACS CATALYSIS; v. 5, n. 5, p. 2778-2787, MAY 2015.
Citações Web of Science: 35
Resumo

Borohydride anions (BH4-) are interesting as fuel for low-temperature alkaline fuel cells, owing to their high hydrogen content and low theoretical potential of oxidation. However, the borohydride electrooxidation mechanism and the potential dependence of the undesirable parallel hydrolysis pathway are not completely understood. In this study, by using a dual thin-layer flow-cell online coupled with a mass spectrometer and a rotating ring-disk electrode, the electrocatalytic activity and the dependence of the molecular hydrogen and hydroxiborane (BH3OH-) formation were investigated for carbon-supported Au, Ag, Pt, and Pd nanoparticles. For Au/C and Ag/C, the H-2 and BH3OH- production presented a peak in the potential region of the first branch of the BOR wave and another increase in the metal oxide region. Pt/C and Pd/C showed accentuated H-2 detection at the OCP, with a sharp decrease to practically zero after the BOR onset. Interestingly, and contrarily to what was observed for Au/C and Ag/C, the RRDE measurements showed BH3OH- production only at higher potentials (Pt- or Pd-oxides). These results were explained on the basis of the higher reactivity of Pt/C and Pd/C for the BOR, in which BHx-like species remain adsorbed and hydrogen is consumed via electrooxidation on their surfaces, at low potentials. On the other hand, Au/C and Ag/C, possessing lower reactivity (lower d-band center), the BH3-like species, produced in the first BOR steps, desorb from their surfaces and are detected at the ring. Concomitantly, at the BOR onset, H-2 is formed, via recombination of adsorbed hydrogen atoms and can be detected by the mass spectrometer because these materials are relatively inactive for the hydrogen oxidation reaction. (AU)

Processo FAPESP: 11/50727-9 - Desenvolvimento de sistemas para produção de hidrogênio e para geração e utilização de energia eletro-química
Beneficiário:Ernesto Rafael Gonzalez
Linha de fomento: Auxílio à Pesquisa - Temático
Processo FAPESP: 12/00877-7 - Investigação de eletrocatalisadores nanoestruturados compostos por Ag e Pd frente a eletrooxidação de íons BH4- em eletrólito alcalino
Beneficiário:Aniélli Martini Pasqualeti
Linha de fomento: Bolsas no Exterior - Estágio de Pesquisa - Mestrado
Processo FAPESP: 13/16930-7 - Eletrocatálise V: processos eletrocatalíticos de interconversão entre as energias química e elétrica
Beneficiário:Edson Antonio Ticianelli
Linha de fomento: Auxílio à Pesquisa - Temático
Processo FAPESP: 11/03672-4 - Investigação da atividade de eletrocatalisadores nanoestruturados para a eletrooxidação de íons BH4- em eletrólito alcalino
Beneficiário:Aniélli Martini Pasqualeti
Linha de fomento: Bolsas no Brasil - Mestrado