Electrochemical reduction of carbon dioxide (CO2) has been studied using a Sn/Cu electrode as the cathode in aqueous KHCO3 solution. The Sn/Cu electrode has been prepared by electrodeposition a Sn-based film on a Cu foil from a sodium citrate aqueous electrolyte containing SnCl2. Here, we have explored the effects of the deposition time, the thickness of the Sn-based film and the electrolysis potential on the faradaic efficiency for producing formate. The results demonstrate that maximum faradaic efficiency of 91.5% is obtained at -1.8 V vs. Ag/AgCl on the Sn/Cu electrode possessing a similar to 325 nm thick Sn-based film which is prepared by electrodeposition for 15 min. The Sn/Cu electrode has big current density and excellent catalytic activity for CO2 reduction compared with the Sn electrode. Copyright (c) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.