Ethanol electro-oxidation in an alkaline medium using Pd/C, Au/C and PdAu/C electrocatalysts prepared by electron beam irradiation

Autor(es)

Geraldes, Adriana Napoleao ^[1] ; da Silva, Dionisio Furtunato ^[2] ; Pino, Eddy Segura ^[2] ; Martins da Silva, Julio Cesar ^[2] ; Brambilla de Souza, Rodrigo Fernando ^[2] ; Hammer, Peter ^[3] ; Spinace, Estevam Vitorio ^[2] ; Oliveira Neto, Almir ^[2] ; Linardi, Marcelo ^[2] ; dos Santos, Mauro Coelho ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed ABC, Ctr Ciencias Nat & Humanas, Lab Eletroquim & Mat Nanoestruturados, BR-09210170 Santo Andre, SP - Brazil

^[2] Comissao Nacl Energia Nucl IPEN CNEN, Inst Pesquisas Energet & Nucl, BR-05508900 Sao Paulo - Brazil

^[3] Univ Estadual Paulista, Inst Quim Araraquara, BR-14800060 Araraquara, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Electrochimica Acta; v. 111, p. 455-465, NOV 30 2013.
• Citações Web of Science: 70

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 90 degrees C, and the best performance of 44 mW cm(-2) in 2.0 mol L-1 ethanol was obtained at 85 degrees C 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. (C) 2013 Elsevier Ltd. All rights reserved. (AU)

• Processo FAPESP: 10/16511-6 - Nanoestruturas para a geração de energia a partir de biocombustível
• Beneficiário: Mauro Coelho dos Santos
• Modalidade de apoio: Auxílio à Pesquisa - Regular