Cu(II)/Cu(0) electrocatalyzed CO2 and H2O splitting

In an earlier report we showed that in concentrated carbonate/bicarbonate solutions, simple Cu(II) salts are highly reactive as water oxidation electro-catalysts. We report here, based on earlier results in the literature, that Cu(0) films on a boron-doped diamond substrate are active toward CO2 reduction to CO and formate. The current densities are higher by similar to 2.8 fold than a bulk polycrystalline copper electrode due to the enhanced surface area of the electroplated Cu(0) films. When combined, the two half reactions, catalyzed by Cu(II) and Cu(0), provide a basis for the net electrochemical splitting of CO2 into CO/HCOO- and O-2 in CO2/HCO3- buffered aqueous solutions. The resulting electrochemical cell is remarkable for the simple nature of the catalysts, solution conditions, and cell configuration.