Synthesis and characterization of quaternary PtRuIrSn/C electrocatalysts for direct ethanol fuel cells

To find a more durable anode with high performance for direct ethanol fuel cells (DEFCs), the present study investigates a series of quaternary electrocatalysts, Pt(30)Ru(30)Ir(40-x)Sn(x)/C (wt.%), for the ethanol electro-oxidation reaction (EOR). The carbon-supported Pt(30)Ru(30)Ir(40-x)Sn(x)/C electrocatalysts were prepared by a known impregnation-reduction (borohydride) method. The microstructure and chemical composition were determined by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM). The activity of the electrocatalysts for EOR was compared to commercial Pt(67)Ru(33)/C (HISPEC5000) using linear sweep voltammetry (LSV) based on similar Pt loading. The results of this study show that electrocatalyst composition with 10 and 20% It (wt.%) exhibit higher electrocatalytic activity than the commercial PtRu electrocatalyst. The single fuel cell testing at 90 degrees C comparing Pt(30)Ru(30)Ir(40-x)Sn(x)/C to commercial Pt(67)Ru(33)/C and Pt(83)Sm(2)/C anodes showed an enhancement of Pt activity (normalized to Pt loading) in the following order: Pt(30)Ru(30)Ir(10)Sn(30) > Pt(30)Ru(30)Sn(40) >= Pt(30)Ru(30)Ir(40) >= Pt(83)Sn(17) > Pt(67)Ru(33). After a long-term performance test, the activity changed to the following order: Pt(30)Ru(30)Ir(10)Sn(30) > Pt3oRu301r40 > Pt(30)Ru(30)Sn(40) > Pt(83)Sn(17) > Pt(62)Ru(33). Pt(30)Ru(30)Ir(10)Sn(30)/C exhibited both a higher performance with a specific power density of 29 mWmg(Pt)(-1) without O(2) backpressure at the cathode and an excellent long-term stability in a DEFC operating at 90 degrees C. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.