Porous tin-based film deposited on copper foil for electrochemical reduction of carbon dioxide to formate

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 ∼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.