Fe-Doped Ceria-Based Ceramic Cathode for High-Efficiency CO₂ Electrolysis in Solid Oxide Electrolysis Cell

In the quest for sustainable energy solutions, solid oxide electrolysis cell (SOEC) emerges as a key technology for converting CO2 into fuels and valuable chemicals. This work focuses on pure ceramic FexSm0.2Ce0.8O2-delta (xFe-SDC) as the fuel electrodes, and Sr-free ceria-based ceramic electrodes can be successfully constructed for x <= 0.05. The incorporation of Fe into the ceria lattice increases the oxygen vacancy concentration and promotes the formation of catalytic sites crucial for the CO2 reduction reaction (CO2RR). Density functional theory calculations indicate that Fe enhances electrochemical performance by decreasing the CO2RR energy barrier and facilitating oxygen ion diffusion. At 800 degrees C and 1.5 V, single cells with 0.05Fe-SDC cathodes manifest attractive performance, attaining current densities of -1.98 and -2.26 A cm(-2) under 50% CO2/CO and pure CO2 atmospheres, respectively. These results suggest the great potential of xFe-SDC electrodes as promising avenues for high-performance fuel electrodes in SOEC.