New electrochemical process for CO2 reduction to from formic acid from combustion flue gases

Abstract

Flow cell technologies for electrochemical reactors were applied to the system for carbon dioxide absorption and its electrochemical reduction. Small flow-by type reactors with two chambers separated by a sheet of ion-exchange membrane were employed for both CO2 absorbtion and reduction. Absorbtion of CO2 into phosphate buffer solutions through the ion exchange membrane and succeeding electrochemical reduction of the absorbed CO2 were studied; and the opimum conditions to form formic acid with high current efficiency were discussed. Formic acid is expected to be available to chemiluminescent reagents for oxidant detections and chemical lamps. Almost 100% in current efficiency of CO2 reduction to form formic acid was realized by using In impregnated lead wire cathode. The applied cell voltage was reduced to under 1.5 V due to sulfur dioxide absorption into counter electrode solution.