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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

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

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Pasqualeti, Anielli M. [1] ; Olu, Pierre-Yves [2, 3] ; Chatenet, Marian [2, 3, 4] ; Lima, Fabio H. B. [1]
Total Authors: 4
[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
Total Affiliations: 4
Document type: Journal article
Source: ACS CATALYSIS; v. 5, n. 5, p. 2778-2787, MAY 2015.
Web of Science Citations: 35

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)

FAPESP's process: 11/03672-4 - Investigation of the catalytic activity of nanostructured electrocatalysts for BH4- ions electrooxidation in alkaline media
Grantee:Aniélli Martini Pasqualeti
Support Opportunities: Scholarships in Brazil - Master
FAPESP's process: 11/50727-9 - Development of systems for hydrogen production and for the generation and utilization of electrochemical energy
Grantee:Ernesto Rafael Gonzalez
Support Opportunities: Research Projects - Thematic Grants
FAPESP's process: 13/16930-7 - Electrocatalysis V: electrocatalytic processes of chemical and electrical energy interconversion
Grantee:Edson Antonio Ticianelli
Support Opportunities: Research Projects - Thematic Grants
FAPESP's process: 12/00877-7 - Investigation of the nanostructured electrocatalysts composed by Ag and Pd for BH4- ions electrooxidation in alkaline media
Grantee:Aniélli Martini Pasqualeti
Support Opportunities: Scholarships abroad - Research Internship - Master's degree