Selective Formation of Formic Acid, Oxalic Acid, and Carbon Monoxide by Electrochemical Reduction of Carbon Dioxide

Abstract Selective formation of formic acid, oxalic acid, and carbon monoxide by electrochemical reduction of carbon dioxide (CO2) is demonstrated using several metallic electrodes in aqueous and nonaqueous electrolytes. The electrode metals catalyze the electrochemical reduction of CO2 and are classified to three groups according to their main products from CO2. In and Pb electrodes as well as Hg electrodes are useful for the selective formation of formic acid by electrochemical reduction of CO2 in aqueous electrolytes. In the case of nonaqueous electrolytes, Pb, Hg, and Tl are useful for oxalic acid, and In, Zn, Au, and Sn electrodes are useful for carbon monoxide. Also, reaction mechanisms of CO2 electrochemical reduction are discussed.