Electrochemical Reduction of Carbon Dioxide on Dual-Film Electrodes Modified With and Without Cobalt (11) and Iron (11)Complexes

Carbon dioxide has been electrochemically reduced to organic substances on dual-film electrodes modified with and without a metal complex. Polymethylpyrrole/molybdenum bl e-modified electrodes yielded methanol, ethanol, and ace-tone as the reduction products. The substitution of the coated film by the Fe(II)-4,5-dihydroxybenzene-l,3-disulfonate complex-immobilized polyaniline/Prussian blue led to the selective formation of lactic acid. Reaction products were found both in the solution and within the coated film, suggesting that the electroreduction f CO2 takes place at active centers existing in the coated film and at the electrode/solution interface. A probable pathway was proposed in which CO2 is hydrogenerated stepwise by Had~, and various products are generated by the cross-linking of adsorbed intermediates. The problems of the depletion of fossil fuels and the buildup of the greenhouse effect have drawn public atten-tion, and there is interest in the chemical conversion of CO2 into organic substances in order to solve these problems. The electrochemical conversion of CO2 to more complex compounds i assumed to be promising since this reaction takes place at room temperature, at atmospheric pressure