Nano-CeO2-Modified Cathodes for Direct Electrochemical CO2 Reduction in Solid Oxide Electrolysis Cells

La0.75Sr0.25Cr0.5Mn0.5O3-δ (LSCM) is a promising cathode for CO2 electroreduction in solid oxide electrolysis cells (SOECs), but its low catalytic activity limits the performance of SOECs. In this work, CeO2 nanoparticles with a size of 3–5 nm were successfully impregnated into an LSCM-Gd0.1Ce0.9O1.95 (GDC) composite cathode to investigate its effects on the CO2 electrochemical reduction. The introduction of CeO2 nanoparticles on the LSCM-GDC cathodes can create more three-phase boundaries (TPBs), improve the CO2 adsorption capability, and facilitate the transportation of oxygen ions between the cathode and the electrolyte. Therefore, the nano-CeO2-modified cathodes show better performance than the conventional LSCM-GDC cathode. The maximum current density of the nano-CeO2-modified cathode is about 90% higher than that of the conventional LSCM-GDC cathode at 1.4 V and 800 °C. Therefore, loading nano-CeO2 onto the LSCM-GDC backbone is an effective way to improve the electrocatalytic performance of the conventional LSCM-GDC cathode.