Conversion of CO₂ into useful chemical products by solid oxide electrolysis cells (SOECs) is a promising technology capable of reducing CO₂ concentration for a carbon-neutral society [1]. This electrochemical device has several advantages such as high-energy efficiency and fast electrode kinetics due to its high operating temperature. Conventionally, Ni/YSZ cermet has been widely used as the cathode material of CO₂ electrolysis system. However, they are prone to degrade under CO₂ atmosphere due to the oxidation of nickel, particle agglomeration, and carbon deposition. Therefore, the development of alternative cathode materials with high electrocatalytic activity and good long-term stability for CO₂ reduction reaction (CO₂RR) is highly needed.

The perovskite-type mixed ionic and electronic conducting (MIEC) oxides are widely investigated as the promising alternatives to the Ni/YSZ cermet cathode. Among them, double perovskite oxides PrBaCo₂O_5+d(PBCO) material is attracting attention because of high oxygen surface exchange, diffusion coefficients and adequate mixed ionic and electronic conductivity. However, this material is easily degraded in the presence of CO₂ impurity, with the formation of BaCO₃ nanoparticles [2]. To overcome this issue, doping the B-site Co cations with transition metals and tailoring the cation mismatch by controlling A-site dopant ratio in PBCO were selected as a novel strategy. As a result, it was proved that co-doping was an effective way to improve both electrochemical and surface chemical stability. Our design strategy could benefit the preparation of highly active and stable cathodes for direct CO₂ reduction for SOECs.

References

[1] Lee, Seokhee, et al. Advanced Energy Materials (2021): 2100339.

[2] Zhu, Lin, et al. Applied Surface Science 416 (2017): 649-655.