On the Electrochemical Reduction of Carbon Dioxide at In Situ Electrodeposited Copper

High faradaic efficiencies and current densities for the electrochemical reduction of to both and are reported at in situ deposited copper on glassy carbon electrodes in aqueous . At 8.3 mA/cm 2 the cumulative yield for and can be essentially faradaic. At 25 mA/cm 2 the overall efficiency for these two products was 79%. The proposed reduction mechanism does not appear to involve the direct electrochemical reduction of , but proceeds through the reaction of weakly adsorbed with electrochemically generated chemisorbed hydrogen at the copper surface. Subsequent reduction of this reduced species probably leads to bridged groups which can be desorbed to give either carbon monoxide or reduced further to give and .