Catalisadores metálicos suportados em biopolímero para aplicação em eletrodos de células a combustível

Abstract

The fuel cell is a promising alternative for energy production, as it has high efficiency and low pollutant emissions. Therefore, research has been carried out to evaluate the behavior of metallic nanoparticles synthesized by chemical reduction of metallic salts through the presence of a chitosan polymer for application in fuel cells. The Pt/Q and PtSn/Q electrocatalysts were synthesized through chemical reduction impregnation to study the physical characterization, which was carried out using the XRD technique, and the electrochemical characterization in an acidic medium, which was carried out using cyclic voltammetry techniques in the absence and presence of ethanol, CO stripping with adsorption potentials of 50 mV and 100 mV with a fixed adsorption time of 5 minutes, and chronoamperometry. It was analyzed that the electrocatalysts presented reflections typical of the phase-centered and poorly crystalline cubic structure. In the CO stripping test, it was observed that CO oxidation to Pt/Q and PtSn/Q occurred at low potentials, showing that these electrocatalysts had good electrocatalytic responses to CO oxidation. Through this test, the electrochemically active surface area of the catalysts was calculated, being 56.569 m2.g-1 for Pt/Q and 22.514 m2.g-1 for PtSn/Q. In relation to the electro-oxidation of ethanol, Pt/Q had good catalytic performance as it presented an increase in current density, while PtSn/Q had an anticipation in the oxidation initiation potential. In chronoamperometry, Pt/Q had the highest current density at the final time, 7.21486 μA.cm-2 for Pt/Q and 5.88676 μA.cm-2 for PtSn/Q, suggesting that the catalyst had a good stability and tolerance to poisonous species.