Reduction of carbon dioxide on partially-immersed Au plate electrode and Au-SPE electrode

Abstract

The electrocatalytic reduction of carbon dioxide was carried out on two types of Au plate electrode; one was partially immersed in electrolyte solution containing CO 2 and the other was completely immersed. Their surface areas in contact with the solution were kept equal, so that the difference in Faradaic efficiency for the reduction of CO 2 to CO between the two types of electrodes was examined. The effects of surface treatments of the electrodes and electrolytes on the Faradaic efficiency were also investigated for each type of electrode. When the electrode surface was treated by electroplating Au on the Au plate, the partially-immersed electrode brought about a higher Faradaic efficiency for CO 2 reduction than the completely immersed one both in 1 mol dm −3 KHCO 3 and in 0.1 mol dm −3 (C 2H 5) 4NClO 4 aqueous solution at room temperature. The Au-SPE (SPE: solid polymer electrolyte) electrode was applied as a gas diffusion electrode to the reduction of CO 2, and the Faradaic efficiency for CO production was compared with that obtained by the partially-immersed Au plate electrode. The Au-SPE electrode gave rise to a higher Faradaic efficiency than the partially-immersed electrode.