PtSnCe/C electrocatalysts for ethanol oxidation: DEFC and FTIR “in-situ” studies |
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Authors: | RFB De SouzaLS Parreira JCM SilvaFC Simões ML CalegaroMJ Giz GA CamaraAO Neto MC Santos |
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Affiliation: | a LEMN - Laboratório de Eletroquímica e Materiais Nanoestruturados, CCNH - Centro de Ciências Naturais e Humanas, UFABC - Universidade Federal do ABC, CEP 09.210-170, Rua Santa Adélia 166, Bairro Bangu, Santo André, SP, Brazil b Grupo de Materiais Eletroquímicos e Métodos Eletroanalíticos, Instituto de Química de São Carlos, Universidade de São Paulo, Caixa Postal 780, 13566-590 São Carlos, SP, Brazil c Departamento Química - DQI, Universidade Federal de Mato Grosso do Sul - UFMS, Av. Fellinto Muller, 1555, P.O. Box 549, 79070-900 Campo Grande, MS, Brazil d Instituto de Pesquisas Energéticas e Nucleares, IPEN, CNEN/SP, Av. Prof. Lineu Prestes, 2242 Cidade Universitária, CEP 05508-900, São Paulo, SP, Brazil |
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Abstract: | The ethanol oxidation reaction (EOR) was investigated using PtSnCe/C electrocatalysts in different mass ratios (72:23:5, 68:22:10 and 64:21:15) that were prepared by the polymeric precursor method. Transmission electron microscopy (TEM) showed that the particles ranged in size from approximately 2 to 5 nm. Changes in the net parameters observed for Pt suggest the incorporation of Sn and Ce into the Pt crystalline network with the formation of an alloy between Pt, Sn and/or Ce. Among the PtSnCe catalysts investigated, the 68:22:10 composition showed the highest activity toward ethanol oxidation, and the current-time curves obtained in the presence of ethanol in acidic media showed a current density 50% higher than that observed for commercial PtSn/C (E-Tek). During the experiments performed on single direct ethanol fuel cells, the power density for the PtSnCe/C 68:22:10 anode was nearly 40% higher than the one obtained using the commercial catalyst. Data from Fourier transform infrared (FTIR) spectroscopy showed that the observed behavior for ethanol oxidation may be explained in terms of a double mechanism. The presence of Sn and Ce seems to favor CO oxidation, since they produce an oxygen-containing species to oxidize acetaldehyde to acetic acid. |
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Keywords: | Ethanol oxidation reaction Electrocatalysis Platinum-tin alloys Ceria Polymeric precursor method |
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