Different mass ratio proportions of PtSn (m/m) electrocatalysts with 20% metal loading on a carbon support were prepared for use in ethanol:methanol solutions oxidation reactions. PtSn/C (3:1) (91% alloy degree, lattice parameter of 0.399 nm and mean crystallite size 4.8 nm) presented the best activity for oxidation of mixed solutions. The highest normalized current (ethanol:methanol 80:20) was 4.2 mA mgPt-1 (measured after 1800 seconds at 0.5 V). Therefore, the PtSn/C (3:1) electrocatalyst with an atomic ratio of 65:35 enhanced both the electronic effect and bifunctional mechanism in (ethanol:methanol 80:20), which resulted in the formation of CO2 at low potentials, as well as the highest amount of by-products than ethanol and methanol.

Neste estudo, a reação de oxidação de etanol (EOR) foi investigada usando materiais nanoestruturados ternários compostos de IrPtSn/C nas proporções em massa Ir:Pt:Sn de 60:30:10, 60:20:20 e 60:10:30, preparados pelo método de precursores poliméricos e comparados com o eletrocatalisador de origem comercial PtSn/C E-TEK. A caracterização por difratometria de raios-X foi utilizada para obter informações acerca da estrutura dos materiais e a microscopia eletrônica de transmissão mostrou que os tamanhos médios das partículas variaram de 5 até 7 nm. A atividade eletrocatalítica foi investigada empregando experimentos cronoamperométricos em 0,5 V vs. RHE e através da espectroscopia no infravermelho com transformada de Fourier no modo de refletância total atenuada (FTIR-ATR) in situ. Baseado nos experimentos de FTIR-ATR in situ, observou-se que o melhor material IrPtSn/C 60:20:20 levou à formação de acetaldeído em altas intensidades e CO2 em baixas intensidades. Utilizando-se o material IrPtSn/C 60:20:20, foi possível diminuir a quantidade de platina em ca. 73% em comparação com o eletrocatalisador PtSn/C E-TEK, tendo um aumento de ca. 282% na densidade de corrente nos experimentos cronoamperométricos.

In this work, the ethanol oxidation reaction (EOR) was investigated using ternary nanostructured materials composed of IrPtSn/C in mass proportions of Ir:Pt:Sn at 60:30:10, 60:20:20 and 60:10:30, prepared with a polymeric precursor method and compared with commercial electrocatalyst PtSn/C E-TEK. X-ray diffractometry was used to obtain information about the structure of the material. The transmission electron microscopy showed particle sizes of 5-7 nm. The electrocatalytic activity was investigated using chronoamperometry experiments at 0.5 V vs. RHE and by in situ Fourier transform infrared spectroscopy by attenuated total reflectance (FTIR-ATR) experiments. From in situ FTIR-ATR experiments, it can be seen that using the best material IrPtSn/C 60:20:20, the acetaldehyde was produced at high intensities and CO2 at lower intensities. The use of IrPtSn/C 60:20:20 materials became possible to diminish the Pt fraction to ca. 73% in comparison to the PtSn/C E-TEK electrocatalyst, with an improvement of ca. 282% in the current density of the chronoamperometric experiments.