Influence of ethanol and ethylene glycol on the preparation of platinumruthenium supported catalysts by electrodeposition

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

La Plata, Buenos Aires

Congreso; 4to Encuentro de Física y Química de Superficies; 2009

INIFTA - Asociación Física Argentina

This paper reports the preparation of carbon supported Pt-Ru by multiple cycles of potentiostatic pulses from diluted solutions of platinum and ruthenium salts at pH 2 or 5 containing ethanol (EtOH) and ethylene glycol (EG) as stabilizers. SEM micrographs of Pt-Ru catalysts over graphite cloth are shown. The electrodeposition method generates rough islands with incipient dendrites at pH 2, whereas globular particles at pH 5 are observed. In addition, SEM images showed that the mean particle size of the Pt-Ru nanoparticles was three or four times smaller in presence of a stabilizer The Ru content of the catalyst prepared without stabilizer appears to be slightly higher than those estimated for the electrodes prepared with EtOH and EG (20 at. % vs. 16 at. %).The electrocatalytic activity measurements indicate that the most active electrode for methanol electro-oxidation was obtained adding EtOH in the deposition solution, followed by EG at pH 2, whereas the inverse dependence is observed at pH 5. From a practical point of view, the electrode prepared with the stabilizers appear to be interesting as materials for applications and not as exclusively model systems, since it combines a good intrinsic activity and a high true surface area that make it possible to obtain good catalytic activity for methanol oxidation.