The surface modification of Pt/C catalyst with Ag and the electrocatalytic oxidation of ethanol on the Ag-modified Pt/C catalysts are investigated. The Ag-modified Pt/C catalysts are prepared by means of the potentiostatic deposition of Ag on the Pt nanoparticles loaded on carbon black and coated on glassy carbon (GC) electrodes. Instrumental analysis and electrochemical analysis show that the metal nanoparticles are well distributed on carbon black and the surface of the Pt nanoparticles is partially covered by Ag. Cyclic voltammetric (CV) results display that the deposition of Ag leads to a significant improvement in the activity of Pt/C for ethanol oxidation in alkaline solution. In a wide range of Ag loadings, the Ag-modified Pt/C catalysts show more negative onset oxidation potential and much higher peak current density than the Pt/C catalyst, though Ag has no catalytic activity for ethanol oxidation. (C) 2014 Elsevier Ltd. All rights reserved.