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

Abstract In the quest for sustainable energy solutions, solid oxide electrolysis cell (SOEC) emerges as a key technology for converting CO 2 into fuels and valuable chemicals. This work focuses on pure ceramic Fe x Sm 0.2 Ce 0.8 O 2‐ δ (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 CO 2 reduction reaction (CO 2 RR). Density functional theory calculations indicate that Fe enhances electrochemical performance by decreasing the CO 2 RR energy barrier and facilitating oxygen ion diffusion. At 800 °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% CO 2 /CO and pure CO 2 atmospheres, respectively. These results suggest the great potential of xFe‐SDC electrodes as promising avenues for high‐performance fuel electrodes in SOEC.