Eletrocatalisadores de PtSn/C em diferentes composições para estudo da eletrooxidação de etilenoglicol para aplicação em células a combustível de álcool direto

Abstract

Among the main alternative energy sources, fuel cells (FC) are characterized by reduction in waste generation and increased energy efficiency. The limitation of hydrogen gas as FC fuel is directing to the use of short-chain alcohols such as ethylene glycol. In this work, the ethylene glycol electrooxidation was studied in PtSn nanoparticles supported on carbon in different compositions, using electrochemical and spectroscopic techniques, aiming its use in Direct Alcohol FuelCells. The PtSn nanoparticles were prepared using formic acid as a reducing agent of Pt and Sn salts. The physicochemical characterization of these electrocatalysts was made by the technical XRD and XDE. The results show that electrocatalysts prepared present a divergent real composition of the nominal composition. The size of the Pt crystallites were in the range of 4 to 6 nm and an increasing in the lattice parameter of Pt was observed indicating alloy formation. The electrochemical results showed that the catalyst PtSn / C (86:14) exhibited a lower electrocatalytic activity, although in situ FTIR experiments have shown less selectivity for CO2formation. The in situ FTIR experiments showed the production of glycolic acid, oxalic acid, formic acid, glyoxal and glycolaldehyde as byproducts of partial oxidation of ethylene glycol.