二酸化炭素の銅・銅酸化物電極を用いた光照射下におけるパルス電解還元(物質生命化学科)

Abstract

Pulsed electroreduction of CO_2 in alkaline solution on copper electrode and cuprous oxide electrode were studied under irradiation. Methane, ethylene and ethanol were reported to be obtained by electroreduction of CO_2 in alkaline solution on copper electrode previously. And more amounts of methane and ethylene were reported to be obtained by the pulsed electroreduction than by the direct electroreduction on copper electrode. We tried to apply pulsed electroreduction of CO_2 in alkaline solution with setting high anodic potential of copper electrode. As the results, we found that in pulse electroreduction using copper electrode, faradic efficiency of methane which was the competitive product of ethylene was decreased, and at higher anodic potential than +0.5V, Cu_2O and CuO were found to be generated on copper electrode surface and act on the reduction of CO_2 in alkaline solution under irradiation. By using Cu_2O electrode instead of Cu electrode in the electroreduction of CO_2, we found that only ethylene was produced selectively, and methane was very little produced, and moreover ethane was produced by addition of palladium-Alumina in cathodic compartments. And, we tried to find the effectivenese of addition of various kinds of metal and metal oxides on the products in this pulsed electroreduction of CO_2 The detailed mechanism of this phenomena will be discussed in the next paper.