Carbon supported ternary Pt₅₂Sn_(36−x)Rh₁₂–Sn_xO_2x electrocatalysts with the average diameter of 2.8 ± 0.5 nm were synthesized using a Polyol process followed by thermal treatment. Several techniques including high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) and extended X-ray absorption fine structure (EXAFS) were used to identify the coexistence of homogeneously distributed Pt/Sn/Rh random alloy and non-alloyed SnO₂ throughout the catalyst. The Pt₅₂Sn_(36−x)Rh₁₂–Sn_xO_2x catalyst showed a superior long-term activity and stability towards ethanol oxidation than the commercial Pt catalyst. Our data of ternary Pt/Sn/Rh catalysts with different chemical compositions and crystalline structures also indicated that the superior performance of Pt₅₂Sn_(36−x)Rh₁₂–Sn_xO_2x might result from the electronic effect of the Pt/Sn/Rh random alloy.