Preparation of cu-solid polymer electrolyte composite electrodes and application to gas-phase electrochemical reduction of CO 2

Abstract

Preparation of Cu-solid polymer electrolyte ( spe) composite electrodes for gas-phase electrochemical reduction of CO 2 was studied by electroless plating methods. Among the combinations of plating solutions and reducing solutions used, the combination of Cu-Rochelle salt and 10% NaBH 4 gave the most efficient spe electrode. With the electrodes made of cation-exchange (Nafion) and anionexchange (Selemion) membranes as spe materials, the total current efficiencies for reduction products of CO 2 had maximum values of 19 and 27%, respectively. The use of the former gave C 2H 4 as the major product, whereas, with the later, HCOOH and CO were obtained. From gas-phase electrolysis of the dummy exhausted gas from thermal-power plants, it was found that NO has no influence on the electroreduction of CO 2, but the removal of SO 2 is needed in order to obtain C 2H 4 in higher current densities. Furthermore CO 2 in the exhausted gas is required to be concentrated up to more than ca. 30%.