Ethanol electro-oxidation in an alkaline medium using Pd/C, Au/C and PdAu/C electrocatalysts prepared by electron beam irradiation
Contribuinte(s) |
Universidade Estadual Paulista (UNESP) |
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Data(s) |
27/05/2014
27/05/2014
11/09/2013
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Resumo |
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. |
Formato |
455-465 |
Identificador |
http://dx.doi.org/10.1016/j.electacta.2013.08.021 Electrochimica Acta, v. 111, p. 455-465. 0013-4686 http://hdl.handle.net/11449/76545 10.1016/j.electacta.2013.08.021 WOS:000329531100061 2-s2.0-84883524606 |
Idioma(s) |
eng |
Relação |
Electrochimica Acta |
Direitos |
closedAccess |
Palavras-Chave | #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 |
Tipo |
info:eu-repo/semantics/article |