As a promising and profound device for energy conversion, a solid oxide electrolysis cell (SOEC) can efficiently convert CO2 to CO, realizing chemical storage of renewable energy. However, developing active and stable cathode catalysts for the CO2 reduction reaction (CO2-RR) is critical for SOECs. Herein, to enhance the electrocatalytic performance of a La0.6Sr0.4Fe0.8Ni0.2O3−δ (LSFN) cathode catalyst for CO2-RR, fluorine doping is investigated as anion doping for O-site in the LSFN perovskite lattice. The results confirm that F-doped La0.6Sr0.4Fe0.8Ni0.2O3−δ (LSFNF0.1) has more oxygen vacancies and better CO2 adsorption ability (approaching 4 times than LSFN). The cell with LSFNF0.1 can achieve a maximum electrolysis current density of 1.93 A·cm–2 at 1.8 V at 850 °C, with a R p of 0.275 Ω·cm2 at OCV. Meanwhile, the cell possesses good durability for more than 60 h at an electrolysis current density of 0.6 A·cm–2 without apparent degradation. Mechanistic analysis indicates that F-doping can accelerate the formation of intermediates during electrolysis, indirectly promoting the reaction of the bidentate carbonate (rate-determining step). This work shows that anion-doped LSFNF0.1 is a promising cathode for SOEC direct CO2 electrolysis and provides a potential route for the cathode catalyst development of SOECs.

No abstract

Symmetric solid oxide cells (SSOCs) have attracted enormous attention because of their simple cell configuration and low fabrication costs. However, their development is limited by the electrocatalytic activity and stability...

No abstract

The main barrier to symmetrical solid oxide cells (SSOCs), where the same catalytic materials are used simultaneously as the anodes and the cathodes, is to find a redox-stable catalyst that exhibits superior catalytic activities for both fuel oxidation/reduction and oxygen reduction/evolution reactions. Here, we report a simple strategy by Sc doping La 0.6 Ca 0.4 Fe 0.8 Ni 0.2 O 3−δ (LCFN) with enhanced electrocatalytic activity and stability in SSOCs. La 0.6 Ca 0.4 Fe 0.7 Sc 0.1 Ni 0.2 O 3−δ (LCFSN) oxide has better crystal structural stability, lower coefficient of thermal expansion (TEC) and good conductivity. In addition, LCFSN has lower polarization resistance both in air, CO 2 or H 2 compared with LCFN. Moreover, the SSOCs with LCFSN showed the maximum power densities of 0.332 and 0.234 W cm −2 when operating in humidified hydrogen at 850 °C and 800 °C, respectively, and the cell shows maximum current densities of 1.093 A cm −2 for CO 2 electrolysis at 850 °C and 1.8 V. In addition, the cell also has good stability toward both fuel cell and electrolysis cell. Therefore, this work suggests that B site Sc doping is a promising approach to the redoxstable catalyst for SSOCs.