High-temperature solid oxide electrolysis cells (SOECs) offer a promising pathway for CO2-to-CO conversion yet are hindered by cathode inactivity. This study demonstrates cation doping in Sr2Ti0. 8Fe1. 2O6-δ (STF), specifically forming Sr2Ti0. 8FeNi0. 2O6-δ (STFN) and Sr2Ti0. 8FeCo0. 2O6-δ (STFC), as an effective strategy for modulating oxygen activity and enhancing CO2 electrolysis performance. The STFC cathode delivers optimal results, achieving a 1. 15 A cm-2 current density, 8. 01 mL min-1 cm-2 CO production rate, and >99% Faradaic efficiency at 1. 6 V and 800 °C. Advanced spectroscopic techniques combined with density functional theory calculations reveal that Co doping increases oxygen activity, evidenced by an upshifted O 2p band center and reduced oxygen vacancy formation energy. Consequently, CO2 adsorption for carbonate (CO32-) intermediate formation is facilitated, and the energy barrier for CO generation is reduced. A techno-economic assessment projects a competitive CO production cost of 748 per ton. These insights provide fundamental guidelines for the design of high-activity catalysts in high-temperature electrochemical systems.
Shang et al. (2026) studied this question.