Iron stabilized 1/3 A-site deficient La-Ti-O perovskite cathodes for efficient CO2 electroreduction

CO2 electroreduction in solid oxide electrolysis cells is appealing for energy storage and CO2 fixation. Highly active electrocatalysts with long-term operation stability are vital for the electrochemical process. Herein, novel 1/3 A-site deficient perovskite cathodes La0.66Ti1-xFexO3-delta (x = 0.2, 0.3 and 0.4) without alkaline-earth elements are synthesized. Compared with Ni and Co, Fe cations demonstrate a unique role in the formation of such Ti-based perovskite structures. These cathodes show superior electrochemical performance to other reported perovskite-type cathodes, with a low polarization resistance of 0.16 omega cm(2) at 1.4 V and 800 degrees C for CO2 electroreduction. La0.66Ti0.8Fe0.2O3-delta exhibits stable electrochemical performance over 300 h with the current density maintained above 0.5 A cm(-2) and faradaic efficiency close to 100%, indicating that these La0.66Ti1-xFexO3-delta perovskites are promising cathodes for CO2 electroreduction. The kinetic process analysis reveals that the cathode can be activated by applied voltages and the rate limiting step is the electron transfer from the cathode to CO2. Surface reconstruction with the electrochemically exsolved iron nanoparticles under applied voltages is observed and shows good electrocatalytic activity towards CO2 electroreduction, indicating that the cathode activity could be tuned via electrochemical methods.