Performance and selectivity of PtxSn/C electro-catalysts for ethanol oxidation prepared by reduction with different formic acid concentrations

Autor(es)

Zignani, Sabrina C. ^[1] ; Baglio, Vincenzo ^[2] ; Linares, Jose J. ^[1] ; Monforte, Giuseppe ^[2] ; Gonzalez, Ernesto R. ^[1] ; Arico, Antonino S. ^[2]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Quim Sao Carlos, BR-13560970 Sao Carlos, SP - Brazil

^[2] CNR ITAE Inst, I-98126 Messina - Italy

• Tipo de documento: Artigo Científico
• Fonte: Electrochimica Acta; v. 70, p. 255-265, MAY 30 2012.
• Citações Web of Science: 39

Resumo

Carbon supported Pt-Sn catalysts were prepared by reduction of Pt and Sn precursors with formic acid and characterized in terms of structure, morphology and surface properties. The electrocatalytic activity for ethanol oxidation was studied in a direct ethanol fuel cell (DEFC) at 70 degrees C and 90 degrees C. Electrochemical and physico-chemical data indicated that a proper balance of Pt and Sn species in the near surface region was necessary to maximize the reaction rate. The best atomic surface composition, in terms of electrochemical performance, was Pt:Sn 65:35 corresponding to a bulk composition 75:25 namely Pt3Sn1/C. The reaction products of ethanol electro-oxidation in single cell and their distribution as a function of the nature of catalyst were determined. Essentially, acetaldehyde and acetic acid were detected as the main reaction products; whereas, a lower content of CO2 was formed. The selectivity toward acetic acid vs. acetaldehyde increased with the increase of the Sn content and decreased by decreasing the concentration of the reducing agent used in the catalyst preparation. According to the recent literature, these results have been interpreted on the basis of ethanol adsorption characteristics and ligand effects occurring for Sn-rich electrocatalysts. (C) 2012 Elsevier Ltd. All rights reserved. (AU)

• Processo FAPESP: 10/07108-3 - Desenvolvimento de estratégias para aumentar a eficiência da reação de oxidação de etanol pelo mecanismo de 12 elétrons, dando CO2 como produto, no contexto das células a combustível de etanol direto
• Beneficiário: José Joaquín Linares León
• Linha de fomento: Bolsas no Brasil - Pós-Doutorado