Ternary Pt-Rh-SnO2/C electrocatalysts with the atomic ratio Pt:Rh:Sn =3:1:x, where x varies from 2 to 6, were synthesized using the modified polyol method followed by thermal treatment. Several techniques used to characterize these electrocatalysts showed they were composed of homogeneous PtRh alloy and SnO2, having all three constituents coexisting in single nanoparticles with the average particle size around 1.4 nm and a narrow size distribution. While all the electrocatalysts investigated exhibited high catalytic activity for ethanol oxidation, the most active one had the composition with the Pt:Rh:Sn =3:1:4 atomic ratio. These ternary-electrocatalysts effectively split the C-C bond in ethanol at room temperature in acidic solutions, which is verified using the in situ IRRAS technique. (C) 2010 Elsevier Ltd. All rights reserved.