MoO2-based cathode for CO2 and H2O electrolysis

This short communication describes a novel MoO2-based cathode and its potential application for solid oxide electrolysis cells. Electrochemical performances of the MoO2-based cathode are investigated with respect to a commercial Ni/YSZ-based cathode for both co-electrolysis (of H2O and CO2) and electrolysis of only CO2 at 750 °C. Under the co-electrolysis mode, the MoO2-based cell and the Ni/YSZ cell show a similar electrochemical performance, while in the CO2 electrolysis mode, the MoO2-based cell demonstrates a much improved electrocatalytic activity compared with the Ni/YSZ cell. This improved electrochemical activity of the MoO2-based cathode under the CO2 electrolysis mode is further investigated by its electrochemical impedance spectroscopy (EIS) study. According to our EIS study, the polarization resistance of the MoO2-based cell is 67% lower than that of the Ni/YSZ-based cell under the open circuit potential. A performance stability study indicates that the MoO2-based cell exhibits a relatively low performance degradation under the CO2 electrolysis mode during its 10-h constant voltage test, and low carbon amount (6.6 wt.%) is detected after the performance stability measurement. These findings suggest the advantages of applying the MoO2-based cathode for the CO2 electrolysis.