Electrochemical reduction of CO2 to CO over Zn in propylene carbonate/tetrabutylammonium perchlorate

Abstract Developing low cost and high efficient electrode for carbon dioxide (CO 2 ) reduction in organic media is essential for practical application. Zn is a cheap metal and has high catalytic effects on CO 2 reduction to carbon monoxide (CO) in aqueous solution. However, little attention has been given to investigate the performance of Zn in organic media for CO 2 reduction. In present work, we have conducted CO 2 reduction in propylene carbonate/tetrabutylammonium perchlorate on Zn due to that propylene carbonate is a widely used industrial absorber, and tetrabutylammonium perchlorate is a commonly used organic supporting electrolyte. In addition, because electrochemical reduction of CO 2 to CO naturally produces H 2 O, we have discussed water effects on CO 2 reduction in propylene carbonate/tetrabutylammonium perchlorate+6.8 wt % H 2 O. Our experiment results reveal that the faradaic efficiency for CO formation reaches to 83%, and the current density remains stable at 6.72 mA/cm 2 at voltage −2.3 V for 4 h. Interestingly, Zn presents higher catalytic activity than Ag, and slightly lower than Au. X-ray photoelectron spectroscopy results confirm that no poisonous species is formed and absorbed on the cathode, which is an important advantage in practical application.