Robust CO2 Electrolysis via In-situ Interfacial Engineering with Exsolved Fe Nanoparticles on a Perovskite Cathode

Abstract

Solid oxide electrolysis cells (SOECs) offer a promising route for electrochemical CO 2 conversation to sustainable fuels, but their widespread adoption is hindered by the lack of cathodes combining high catalytic activity and stability. To address this challenge, we developed an in-situ interface-engineered La 0.6 Sr 0.4 Fe 0.95 Ti 0.2 O 3-δ cathode (R-LSF 0.95 T) cathode featuring exsolves Fe nanoparticles. The optimized R-LSF 0.95 T-based cell delivers a current density of 780 mA cm -2 at 1.5 V and 800 °C in pure CO 2 atmosphere, representing a 23.2% improvement over mechanically mixed electrode. This performance enhancement arises from synergistic metal-oxide hetero-interfaces, where the reduced perovskite substrate promotes CO 2 adsorption and oxygen-ion transport, while the Fe nanoparticles provide abundant active sites and reduce activation barrier for CO 2 reduction. Notably, the Fe-decorated perovskite demonstrates superior carbon deposition compared to Ni-based cathodes owing to its moderate activity. Consequently, the electrolysis cell maintains exceptional stability over 100 h at 1.5V and 800 ℃, with interfacial robustness further enhanced through redox cycling due to reinforced anchoring effect with more minute Nano-Fe exsolution. This work establishes a novel materials design paradigm that reconciles the activity-stability trade-off in SOEC cathodes through the combination of moderately active catalysts with interface reinforcement, offering new pathways for developing durable, high-performance CO 2 electrolysis systems.