Optimizing CO<sub>2</sub> Electrolysis Performance on Oxygen Vacancy Modulation for La<sub><i>x</i></sub>Sr<sub>2–<i>x</i></sub>TiFeO<sub>6</sub> Perovskite in a Solid Oxide Electrolysis Cell
Xiang Wang, Haoran Wang, Min Li, Xiaolin Xiang, Fuli Wang, Zhibin Yang
Abstract
In order to exploit cost-effective and sustainable solid oxide electrolysis cell (SOEC) devices, the selection of efficient and durable fuel electrodes for the application is crucial. Herein, the improvement of the carbon dioxide (CO 2 ) electrolysis performance for La x Sr 2– x TiFeO 6 (L x STF, where x = 0, 0.1, 0.2, and 0.3) double perovskite is studied on oxygen vacancy modulation. La doping not only causes lattice expansion in cubic phase perovskite oxides but also significantly increases the content of surface oxygen species. Compared to the original Sr 2 TiFeO 6 (STF) perovskite oxide, the concentration of oxygen vacancies and CO 2 adsorption capacity of the La 0.1 Sr 1.9 TiFeO 6 (LSTF01) material are significantly improved. Based on electrochemical analysis, the doping of La element promotes the oxygen-ion conduction process and facilitates CO 2 adsorption during the CO 2 reduction reaction (CO 2 RR), which results in the lowest polarization resistance ( R p ) value of 0.70 Ω·cm 2 at open-circuit voltage and the highest peak current density of 0.95 A·cm –2 at 800 °C for the LSTF01 material. This work provides a highly effective strategy to modulate oxygen vacancies for optimization of the fuel electrode material for SOEC.