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http://acervodigital.unesp.br/handle/11449/76545
- Title:
- Ethanol electro-oxidation in an alkaline medium using Pd/C, Au/C and PdAu/C electrocatalysts prepared by electron beam irradiation
- Universidade Federal do ABC (UFABC)
- Instituto de Pesquisas Energéticas e Nucleares (IPEN)
- Universidade Estadual Paulista (UNESP)
- 0013-4686
- Carbon-supported Pd, Au and bimetallic PdAu (Pd:Au 90:10, 50:50 and 30:70 atomic ratios) electrocatalysts were prepared using electron beam irradiation. The obtained materials were characterized by energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD) and transmission electron microscopy (TEM), and their catalytic activities toward ethanol electro-oxidation were evaluated in an alkaline medium using electrochemical techniques, in situ attenuated total reflectance Fourier transformed infrared spectroscopy (ATR-FTIR) analysis and a single alkaline direct ethanol fuel cell (ADEFC). EDX analyses showed that the actual Pd: Au atomic ratios were very similar to the nominal ones. X-ray diffractograms of PdAu/C electrocatalysts evidenced the presence of Pd-rich (fcc) and Au-rich (fcc) phases. TEM analysis showed a homogeneous dispersion of nanoparticles on the carbon support, with an average size in the range of 3-5 nm and broad size distributions. Cyclic voltammetry (CV) and chronoamperometry (CA) experiments revealed the superior ambient activity toward ethanol electro-oxidation of PdAu/C electrocatalysts with Pd: Au ratios of 90:10 and 50:50. In situ ATR-FTIR spectroscopy measurements have shown that the mechanism for ethanol electro-oxidation is dependent on catalyst composition, leading to different reaction products, such as acetaldehyde and acetate, depending on the number of electrons transferred. Experiments on a single ADEFC were conducted between 50 and 900 C, and the best performance of 44 mW cm-2 in 2.0molL-1 ethanol was obtained at 850C for the Pd:Au 90:10 catalysts. This superior performance is most likely associated with enhancement of ethanol adsorption on Pd, oxidation of the intermediates, the presence of gold oxide-hydroxyl species, low mean particle diameters and better distribution of particles on the support. © 2013 Elsevier Ltd. All rights reserved.
- 11-Sep-2013
- Electrochimica Acta, v. 111, p. 455-465.
- 455-465
- Alkaline direct ethanol fuel cell
- DAAFC
- Electron beam irradiation
- Ethanol electro-oxidation
- Fuel cell
- PdAu/C
- Attenuated total reflectance
- Electrochemical techniques
- Energy dispersive x-ray analysis (EDX)
- Fourier transformed infrared spectroscopy
- Carbon
- Catalyst activity
- Chronoamperometry
- Cyclic voltammetry
- Direct ethanol fuel cells (DEFC)
- Electrocatalysts
- Electrolysis
- Electron beams
- Electrooxidation
- Ethanol
- Experiments
- Fourier transform infrared spectroscopy
- Fuel cells
- Irradiation
- Reaction intermediates
- Transmission electron microscopy
- X ray diffraction
- Palladium
- http://dx.doi.org/10.1016/j.electacta.2013.08.021
- Acesso restrito
- outro
- http://repositorio.unesp.br/handle/11449/76545
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