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Please use this identifier to cite or link to this item: 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
Author(s): 
Institution: 
  • Universidade Federal do ABC (UFABC)
  • Instituto de Pesquisas Energéticas e Nucleares (IPEN)
  • Universidade Estadual Paulista (UNESP)
ISSN: 
0013-4686
Abstract: 
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.
Issue Date: 
11-Sep-2013
Citation: 
Electrochimica Acta, v. 111, p. 455-465.
Time Duration: 
455-465
Keywords: 
  • 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
Source: 
http://dx.doi.org/10.1016/j.electacta.2013.08.021
URI: 
Access Rights: 
Acesso restrito
Type: 
outro
Source:
http://repositorio.unesp.br/handle/11449/76545
Appears in Collections:Artigos, TCCs, Teses e Dissertações da Unesp

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