An electrosynthesis method to obtain Au nanoparticles dispersed on carbon Vulcan XC-72R support material was done using AuX4 – (X = Cl–, Br–, and OH–) as molecular precursors and different electrolyte media. The Au surface structure was significantly enhanced using KOH as an electrolyte as opposed to KBr and H2SO4. Cyclic voltammetry was used as a surface sensitive technique to illustrate the Au/Vulcan XC-72R catalytic activity for the ethanol oxidation reaction (EOR). The Au electroactive surface areas obtained were 1.88, 5.83, and 13.96 m2 g–1 for Au/C–H2SO4, Au/C–KBr, and Au/C–KOH, respectively. The latter compares to chemically reduced Au/C–spheres that had an electroactive surface area of 15.0 m2 g–1. The electrochemical Au electrodeposition, in alkaline media (Au/C–KOH), exhibited the highest catalytic activity for the EOR with a 50% increase in peak current density when compared with Au nanoparticles prepared by the chemical reduction route. Raman and X-ray photoelectron spectroscopies analyses of the Au/Vulcan XC-72R nanomaterials revealed a restructuring of the carbon functionalities responsible for the metal nanoparticle anchoring. Our results strongly suggest that the enhanced EOR catalytic activity is related to the presence of oxygen functional groups on the carbon surface, particularly ketonic groups on the carbon Vulcan XC-72R substrate.