Ethanol oxidation on a high temperature PBI-based DEFC using Pt/C, PtRu/C and Pt3Sn/C as catalysts

Autor(es)

Linares, Jose J. ; Zignani, Sabrina C. ; Rocha, Thairo A. ; Gonzalez, Ernesto R.

• Tipo de documento: Artigo Científico
• Fonte: Journal of Applied Electrochemistry; v. 43, n. 2, p. 12-pg., 2013-02-01.

Resumo

A high temperature ethanol-fed polymer electrolyte membrane fuel cell has been implemented by using H3PO4-doped m-polybenzimidazole as polymeric electrolyte. Commercial Pt/C, PtRu/C and Pt3Sn/C catalysts are used in the anode. The performance was assessed in terms of polarization curves at different temperatures, feeding the cell with a high concentration ethanol solution (water/ethanol mass ratio of 2). The product distribution was measured with the support of a gas chromatograph. The use of bimetallic catalysts increased the current density. PtRu/C showed the best performance up to 175 A degrees C, but it is outperformed by Pt3Sn/C at 200 A degrees C. In terms of oxidation products, higher temperatures and current densities favour the oxidation of ethanol. However, Pt3Sn/C promoted the generation of more oxidized products compared to PtRu/C (in which most of the ethanol is oxidized to acetaldehyde), especially at high temperature. This accounts for the large current density. In terms of complete oxidation of ethanol to CO2, Pt/C was by far the most efficient catalyst for C-C scission, achieving percentages of 56 % of CO2, although operating above 175 A degrees C dramatically boosted an undesirable methanation process that slashed the efficiency. The combination of fuel cell results and product distribution helped to suggest the different oxidation routes on the surface of the different catalysts. (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
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado