Ruddlesden-Popper oxide SrEu2Fe2O7 as a promising symmetrical electrode for pure CO2 electrolysis

Nowadays, effective utilization of CO2 has been a worldwide issue. Among numerous CO2 conversion devices, solid oxide electrolysis cells (SOECs) have drawn special attention due to their high energy conversion efficiency, great potential in carbon cycling, and low environmental impacts. Compared with the typical ones taking asymmetrical configuration, symmetrical SOECs adapting the same oxide materials as both the cathode and anode have the advantages of simplified fabrication procedures, reduced processing costs and minimized compatibility issues. As the appropriate sites for CO2 conversion, cathodes play the key role in determining the performance of symmetrical SOECs, and thus, attract more attention to improve their electrocatalytic behaviors and endurance via exploring novel materials. In this work, Eu-doped Ruddlesden-Popper (R-P) oxide, SrEu2Fe2O7 (SEF), is applied as an electrode material for symmetrical SOECs to directly electrolyze pure CO2. The outstanding structural stability and excellent electrochemical activity of the SEF electrode under both oxidizing and reducing atmospheres are demonstrated, and relatively low polarization resistances of 0.07 omega cm(2) in air and 0.48 omega cm(2) in 2CO(2)-CO mixtures at 800 degrees C are observed. A great current density of 1.27 A cm(-2) at an applied voltage of 1.5 V and 800 degrees C is achieved on this symmetrical SOEC. An extremely low polarization resistance of 0.27 omega cm(2) is also observed under open circuit conditions. Further, the symmetrical button cell has demonstrated excellent stability within 260 h of the long-term CO2 electrolysis test.

Automated summary

The utilization of CO2 has become a worldwide pressing issue. Solid oxide electrolysis cells (SOECs) have gained special attention due to their high energy conversion efficiency and potential in carbon cycling. Symmetrical SOECs using the same oxide materials for both the cathode and anode offer advantages such as simplified fabrication procedures, reduced costs, and minimized compatibility issues.