Carbon supported Pt–Sn/SnO2 anode catalyst for direct ethanol fuel cells

Abstract

Binary Pt–Sn/SnO₂–C electro-catalysts comprising Pt and Sn in varying weight ratio, namely 31 : 9, 33 : 7 and 35 : 5, were synthesized by an alcohol-reduction process using ethylene glycol as solvent and reducing agent. The electro-catalysts were characterized by XRD, XPS, TEM, SEM-EDAX, ICP-OES, Cyclic Voltammetry (CV), chronoamperometry and CO stripping techniques. XRD spectra reveal shifting of Pt diffraction peaks to lower angles with the addition of Sn compared with Pt–C and also the presence of SnO₂. XPS results also confirm the presence of Sn in the form of PtSn alloy and in the form of SnO₂ phase in the catalyst. The effect of composition towards electro-oxidation of ethanol has been studied by the CV technique. The direct ethanol fuel cells (DEFCs) with Pt–Sn/SnO₂–C anode catalyst with reduced Pt loading exhibits an enhanced peak power density of 27.0 mW cm⁻² while a peak power-density of only 2.2 mW cm⁻² is obtained for the DEFC employing Pt–C at 90 °C.