Different activated biocarbons (aBCs) were prepared from Eucalyptus grand's wood and activated Vulcan carbons (aVCs) were prepared from commercial Vulcan XC72 carbon. These carbon materials were used as a support in a PtSn/C electrocatalysts for ethanol electro-oxidation (EEO). Structural, morphological and chemical composition differences of the electrocatalysts were correlated to their electrocatalytic performance, and by in-situ Fourier Transform Infrared Spectroscopy in the Attenuated Total Reflectance mode (in-situ ATR-FTIRS), with the ethanol electro-oxidation mechanism (EEOM) pathways and product distributions at different potentials using sulfuric acid as a base electrolyte. The nature of the carbon support and it activation method affected the morphological and structural characteristics of the PtSn based electrocatalysts. The electrocatalytic performance of the electrocatalysts supported on the aBCs was better than that of the supported on the activated Vulcan carbons. The PtSn electrocatalysts using CO2 activated biocarbon support had a higher electrochemically active surface area (EASA), lower onset potential and greater current density for the EEO. It was determined that the EEO on all studied PtSn electrocatalysts in sulfuric acid media occurs mainly through the acetic acid and acetaldehyde production. (C) 2016 Elsevier B.V. All rights reserved.