Ethanol electro-oxidation on carbon-supported Pt3Sn/C, Pt3Cu/C and PtSnCu/C catalysts: CV and in situ FTIR study

Abstract

Carbon-supported PtSnCu/C, Pt3Sn/C, Pt3Cu/C and Pt/C electrocatalysts were synthesized by chemical reduction of metal precursors in ethanol reflux. These materials were characterized by energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), transmission electron microscopy (TEM) and applied to the ethanol electro-oxidation in acidic medium. The reaction kinetics was studied by cyclic voltammetry and the mechanism was explored by in situ Fourier transform infrared spectroscopy (FTIR). The investigated materials presented chemical composition close to the nominal ones. XRD results indicated the formation of solid solution of Pt and Cu and/or Sn in the bi and tri-metallic materials. The particle size distribution was narrow with mean particle size of around 3 nm. A homogeneous distribution of the nanoparticles over the carbon support was evidenced. The investigated catalysts were active towards the ethanol oxidation reaction in acidic medium and led to the formation of CO2 and carbonyl compounds, as evidenced by FTIR. PtSnCu/C and Pt3Cu/C started to produce CO2 at 0.70 V vs. RHE, while this product was detected only at 0.75 V and 0.80 V vs. RHE on Pt and Pt3Sn/C, respectively, suggesting that Cu improves the dissociative adsorption of ethanol.