Pt and Pt-Sn nanoparticles were synthesized and supported onto carbon nanotubes (CNT), the electrocatalytic activity towards the ethanol oxidation reaction was analyzed. The effect of the solvent employed for the synthesis was evaluated. Metal nanoparticles synthesis was made using water (Pt-Sn/CNT-W) or ethanol (Pt-Sn/CNT-E) as a solvent. Pt-Sn/CNT-W material presented only Pt-Sn alloy nanoparticles homogeneously distributed on the carbon nanotubes support. Pt-Sn/CNT-E sample showed non well-dispersed nano particles forming agglomerates along the CNTs surface with predominantly Sn4+ superficial species (SnO2) as show the XPS, FTIR and electrochemical results. These surface arrangements had important effects on the electrocatalytic properties. Pt-Sn/CNT-W shows higher ethanol electrooxidation activity than the Pt-Sn/CNT-E, which is attributed to: a) the double catalytic effect and the intrinsic electronic mechanism favored by the presence of Sn; b) the good particle dispersion of the bimetallic active phase on the CNT and; c) the absence of SnO2 species. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.