Infiltration of Ce0.8Gd0.2O1.9 nanoparticles on Sr2Fe1.5Mo0.5O6-δ cathode for CO2 electroreduction in solid oxide electrolysis cell

Solid oxide electrolysis cell (SOEC) can electrochemically convert CO 2 to CO at the gas-solid interface with a high current density and Faradaic efficiency, which has attracted increasing attentions in recent years. Exploring efficient catalyst for electrochemical CO 2 reduction reaction (CO 2 RR) at the cathode is a grand challenge for the research and development of SOEC. Sr 2 Fe 1.5 Mo 0.5 O 6- δ (SFM) is one kind of promising cathode materials for SOEC, but suffers from insufficient activity for CO 2 RR. Herein, Gd 0.2 Ce 0.8 O 1.9 (GDC) nanoparticles were infiltrated onto the SFM surface to construct a composite GDC-SFM cathode and improve the CO 2 RR performance in SOEC. The current density over the GDC infiltrated SFM cathode with a GDC loading of 12.8 wt% reaches 0.446 A cm −2 at 1.6 V and 800 °C, which is much higher than that over the SFM cathode (0.283 A cm −2 ). Temperature-programmed desorption of CO 2 measurements suggest that the infiltration of GDC nanoparticles significantly increases the density of surface active sites and three phase boundaries (TPBs), which are beneficial for CO 2 adsorption and subsequent conversion. Electrochemical impedance spectroscopy results indicate that the polarization resistance of 12.8 wt% GDC-SFM cathode was obviously decreased from 0.46 to 0.30 Ω cm 2 after the infiltration of GDC nanoparticles.