XII Iberian Meeting of Electrochemistry XVI Meeting of the ...

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XII Iberian Meeting of Electrochemistry & XVI Meeting of the Portuguese Electrochemical Society PC 02 Carbon paper-supported Pd nano-materials for the oxygen reduction reaction Rosa Rego, 1 C ristina Oliveira 1 , Ana Maria Rego 2 1 Departamento de Química, Centro de Química - Vila Real, Universidade de Trás-os-Montes e Alto Douro, Apartado 1013, 5001-801 Vila Real, Portugal 2 Centro de Química-Física Molecular and IN, DEQB, Instituto Superior Técnico, Technical University of Lisbon, Av. Rovisco Pais 1049-001 Lisboa, Portugal mcris@utad.pt Most challenges related with polymer electrolyte membrane fuel cells (PEMFC) comprises the development of electrodes materials with high electroactivity, surface area, life time and low cost. For these reasons, the processes of synthesis of the electrocatalyst and deposition onto a gas diffusion layer have become a matter of basic and applied research [1]. One promising method to minimize electrocatalyst particles size, increase its is the electroless deposition process [2-4]. Using this deposition methodology the catalyst can be directly deposited on a commercial gas diffusion layer (GDL), such as a carbon paper, producing well dispersed clusters of nanoparticles. When these clusters are used as electrodes in a fuel cell, not only the surface area becomes large, but also the gas and the electrolyte easily permeates across, gaining straight access to the catalyst. This methodology will be applied to the preparation of Pd cathode catalysts on carbon paper impregnated with an hydrophobic material. Its activity towards oxygen reduction reaction in acid and alkaline media, will be evaluated envisaging the application of this material to a PEMFC. The new nano-Pd materials will be also characterized by SEM/EDS, TEM, DRX and XPS techniques. References [1] Martín, A. J.; Chaparro, A. M.; Galhardo, B.; Folgado, M. A.; Daza, L. J. of Power Sources, 2009, 192, 14. [2] Fujii, T.; Ito, M. Fuel Cells, 2006, 5, 356. [3] Beard, K. D.; Schaal, M. T.; Van Zee, J. W.; Monnier, J. R. Appl. Catal. B: Environmental, 2007, 72, 262. [4] Beard, K. D.; Van Zee, J.W.; Monnier, J. R. Appl. Catal. B: Environmental, 2009, 88, 185. September, 811, 2010. ISEL - Lisbon 80
XII Iberian Meeting of Electrochemistry & XVI Meeting of the Portuguese Electrochemical Society PC 03 Formation of mixed self-assembled monolayers of mono- and dithiols on Au(111) Rafael C. González-Cano, Rafael Madueño, Manuel Blázquez, Teresa Pineda Dpto. Química Física y Termodinámica Aplicada, Universidad de Córdoba, Córdoba, SPAIN tpineda@uco.es Alkanedithiolate self-assembled monolayers (SAMs) can form on Au(111) singlecrystal electrodes by the spontaneous formation of a strong gold-sulfur bond with one of the SH terminal groups and the attractive van der Waals forces between adjacent alkyl chains. The control of the organization of these architectures is of great technological importance, and the formation of well-organized layers is needed. In these layers, the second unreacted thiol moieties should be exposed to the outer surface [1,2]. To obtain compact dithiol layers of standing-up molecules, the use of a mixture of monothiol and dithiol derivatives at the appropriate relative concentrations that results in an almost pure dithiol film, have been reported [3]. In this work, we report on the formation of a mixed layer of octanedithiol (ODT) and octanethiol (OT). The formation process is carried out under electrochemical control. Thus, an exploration of the different experimental conditions of ODT/OT molar ratio, electrochemical deposition potential and deposition time is described. Figure 1. Cyclic voltammograms for the oxidative deposition of ODT and OT layer in 0.1 M NaOH solution on Au(111) single crystal electrode. In Figure 1, the oxidative deposition of ODT and OT in alkaline solutions are shown. It can be deduced that the different peak potentials will drive the formation of a mixed layer depending on the ratio of molecules employed. Acknowledgments: Project CTQ2007/62723, Junta de Andalucía and Universidad de Córdoba. References [1] García Raya, D.; Madueño, R.; Sevilla, J.M.; Blázquez, M.; Pineda, T.; Electrochim. Acta, 2008, 53, 8026. [2] García Raya, D.; Madueño, R.; Blázquez, M.; Pineda, T.; J. Phys. Chem. C, 2010, 114, 3568. [3] Jiang, W. R.; Zhitenev, N.; Bao, Z. N.; Meng, H.; Abusch-Magder, D.; Tennant, D.; Garfunkel, E. Langmuir 2005, 21, 8751. September, 811, 2010. ISEL - Lisbon 81
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