PREPARATION OF SUPPORTED Pt-Ru CATALYSTS BY SUCCESIVE CYCLES OF POTENTIOSTATIC PULSES: EVALUATION OF NAFION® 117 FILM EFFECT IN METHANOL OXIDATION

J.M. SIEBEN; M.M.E. DUARTE; C.E. MAYER

San Juan, San Juan

Congreso; HYFUSEN 2009: 3er Congreso Nacional, 2do Congreso Iberoamericano; 2009

Instituto de Energía y Desarrollo Sustentable - CNEA - Facultad de Ing. de la Univ. de San Juan - Inst. de Energía Eléctrica

Diverse electrochemical techniques together with electrochemical impedance spectroscopy (EIS)measurements were performed in order to obtain meaningful information about the methanol oxidationreaction on nanostructured planar carbon supported Pt-Ru electrodes prepared by electrodeposition, on which a layer of Nafion® ionomer was incorporated. A decrease of the activity in the electrodes and an increase in the Tafel slope were determined when the thickness of a Nafion® 117 film wasincreased. These results may be associated with the partial blocking of the surface active sites byhydrophobic domains of the polymer, and the presence of CO2 molecules retained in the Nafion®hydrophilic microchannels. EIS results indicated that methanol electro-oxidation mechanism does notchange with Nafion® presence.