ECS Transactions [ECS 218th ECS Meeting - Las Vegas, NV (October 10 - October 15, 2010)] - RRDE and...
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RRDE and EIS study of Pt-Co/MWCNT electro- catalysts as ORR electrodes in sulfuric acid containing small organic molecules F.J. Rodríguez Varela 1,* , D.K. López de la Fuente 2 , D. Morales-Acosta 3 , L.G. Arriaga 3 1 Grupo de Recursos Naturales y Energéticos Cinvestav Unidad Saltillo Carr. Saltillo-Monterrey km 13.5, Ramos Arizpe, Coahuila, C.P. 25900, Mexico 2 Facultad de Ciencias Químicas, Universidad Autónoma de Coahuila. Blvd. Venustiano Carranza S/N, Saltillo, Coahuila, C.P. 25280, Mexico 3 CIDETEQ, Parque Tecnológico Querétaro, Sanfandila, Pedro Escobedo, C. P. 76703 Querétaro, México ( * [email protected]) In this work, the catalytic activity of Pt-Co/MWCNT for the ORR was evaluated in acid solutions containing small organic molecules that have been suggested as candidate fuels for Direct Alcohol Fuel Cells (DAFC) such as ethanol 1,2 and ethylene glycol 3,4 . In organic substance-free electrolytes, the RRDE results indicate that the ORR on the supported Pt-Co alloy follows a 4 electron path, with a very small production of hydrogen peroxide, as seen in Figure 1. The EIS measurements show one arc in the complex plane spectrum that may correspond to a single time constant that results from H 2 O formation at this cathode, confirming the low H 2 O 2 production rate on the alloy. Meanwhile, in the presence of the organic substances, the Pt-Co electro-catalyst showed a high selectivity toward the ORR and full tolerance to those fuels. Moreover, the Nyquist spectrums indicate similar characteristics without and with liquid substances, which suggests that the ORR mechanism might not change at Pt-Co/MWCNT under experimental conditions that may be found in DAFCs. Figure 1. Disc and ring ORR currents at Pt-Co/MWCNT. Electrolyte: 0.5M H 2 SO 4 . Scan rate: 10 mV/s. ω: 1600 rpm. References. 1. O. Savadogo and F. J. Rodríguez Varela, J. New Mat. Electrochem. Systems, 11, 69 (2008). 2. F.J. Rodríguez Varela and O. Savadogo, Asia-Pac. J. Chem. Eng., 4, 17 (2009). 3. V. Livshits, A. Philosoph, E. Peled, J. Power Sources, 178, 687 (2008). 4. D. Morales-Acosta, L.G. Arriaga, L. Alvarez- Contreras, S. Fraire Luna and F.J. Rodríguez Varela, Electrochem. Commun., 11, 1414 (2009). Abstract #955, 218th ECS Meeting, © 2010 The Electrochemical Society ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 193.140.28.22 Downloaded on 2014-11-09 to IP
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Transcript of ECS Transactions [ECS 218th ECS Meeting - Las Vegas, NV (October 10 - October 15, 2010)] - RRDE and...
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RRDE and EIS study of Pt-Co/MWCNT electro-catalysts as ORR electrodes in sulfuric acid containing
small organic molecules
F.J. Rodríguez Varela1,*, D.K. López de la Fuente2, D. Morales-Acosta3, L.G. Arriaga3
1Grupo de Recursos Naturales y Energéticos Cinvestav Unidad Saltillo
Carr. Saltillo-Monterrey km 13.5, Ramos Arizpe, Coahuila, C.P. 25900, Mexico
2Facultad de Ciencias Químicas, Universidad Autónoma de Coahuila.
Blvd. Venustiano Carranza S/N, Saltillo, Coahuila, C.P. 25280, Mexico
3CIDETEQ, Parque Tecnológico Querétaro, Sanfandila, Pedro Escobedo,
C. P. 76703 Querétaro, México (*[email protected])
In this work, the catalytic activity of Pt-Co/MWCNT for the ORR was evaluated in acid solutions containing small organic molecules that have been suggested as candidate fuels for Direct Alcohol Fuel Cells (DAFC) such as ethanol1,2 and ethylene glycol3,4. In organic substance-free electrolytes, the RRDE results indicate that the ORR on the supported Pt-Co alloy follows a 4 electron path, with a very small production of hydrogen peroxide, as seen in Figure 1. The EIS measurements show one arc in the complex plane spectrum that may correspond to a single time constant that results from H2O formation at this cathode, confirming the low H2O2 production rate on the alloy. Meanwhile, in the presence of the organic substances, the Pt-Co electro-catalyst showed a high selectivity toward the ORR and full tolerance to those fuels. Moreover, the Nyquist spectrums indicate similar characteristics without and with liquid substances, which suggests that the ORR mechanism might not change at Pt-Co/MWCNT under experimental conditions that may be found in DAFCs.
Figure 1. Disc and ring ORR currents at Pt-Co/MWCNT. Electrolyte: 0.5M H2SO4. Scan rate: 10 mV/s. ω: 1600 rpm. References. 1. O. Savadogo and F. J. Rodríguez Varela, J. New Mat.
Electrochem. Systems, 11, 69 (2008).
2. F.J. Rodríguez Varela and O. Savadogo, Asia-Pac. J. Chem. Eng., 4, 17 (2009).
3. V. Livshits, A. Philosoph, E. Peled, J. Power Sources, 178, 687 (2008).
4. D. Morales-Acosta, L.G. Arriaga, L. Alvarez-Contreras, S. Fraire Luna and F.J. Rodríguez Varela, Electrochem. Commun., 11, 1414 (2009).
Abstract #955, 218th ECS Meeting, © 2010 The Electrochemical Society
) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 193.140.28.22Downloaded on 2014-11-09 to IP
