Estudo da oxidação eletroquímica do etanol em meio alcalino utilizando eletrocatalisadores PtAuIr/C e PdAuIr/C preparados via redução por borohidreto de sódio

Abstract

in different atomic proportions, with 20 wt.% of metal loading and supported on Vulcan XC72 carbon with high surface area. The materials were characterized by X-ray dispersive energy spectroscopy (EDX), X-ray diffraction analysis (XRD) and transmission electron microscopy (TEM). The ethanol electrochemical oxidation was studied by cyclic voltammetry (CV), chronoamperometry and in situ using Fourier Transform Infrared Spectroscopy (FTIR) using the thin porous coating technique, Afterwards the materials were tested on direct ethanol alkaline fuel cells. The results suggest alloys formation, with the mean nanoparticles sizes are from 4-10 nm. According to the electrochemical experiments the ternary electrocatalysts presented higher electrocatalytic activity, while that the FTIR studies indicated that the main product of the electrochemical oxidation of ethanol in alkaline medium for all synthesized electrocatalysts was acetate, also suggesting that the oxidation occurs incompletely by the indirect mechanism. The fuel cell experiments showed the best results for PdAuIr/C (50:40:10), where these materials had an open circuit potential of approximately 0,78 V and maximum power density of about 15 mW cm-2 , about 333% higher than Pd/C.

Oxidação eletroquímica do etanol e glicerol em eletrólito alcalino utilizando eletrocatalisadores PdTiO>sub<2>/sub</C preparados via redução por borohidreto de sódio

“…Nos experimentos, em uma célula a combustível unitária alcalina, utilizam-se componentes como membrana, eletrodos e camadas difusoras (que devem ser preparados adequadamente). Neste sentido os procedimentos realizados foram baseados na literatura [174][175][176].…”