Fabrication of Ag2S electrode for CO2 reduction in organic media

Electro-reduction of carbon dioxide (CO2) to carbon monoxide (CO) has been extensively studied on metal and alloy electrodes for many decades. However, owing to their disadvantages of low current density and high over-potential, the practical application of these electrodes has been limited. Hence, it is highly desirable to explore new and high efficient electrode for CO2 reduction to CO. Ag2S has been widely studied as electrode material in electrochemistry due to its unique properties, such as high conductivity, chemical stability, and easy to be prepared. In this work, we have fabricated an Ag2S electrode via electro-oxidation of Ag in aqueous solution. X-ray diffraction (XRD) and scanning electron microscope (SEM) confirm that Ag2S has been modified on Ag foil, which made the electrode surface roughness. And then, we have evaluated the performance of Ag2S electrode as the cathode for CO2 reduction in propylene carbonate/tetrabutylammonium perchlorate. The cathodic current density reaches to 9.85 mA/cm2, with the faradic efficiency for CO formation remaining stable at 92% during 4 h long-term electrolysis.