<i>In situ</i> exsolving RuFe/La0.6Sr0.4Fe0.95Ru0.05O3-δ interfaces for direct and ethane-intensified CO2 electrolysis in solid oxide electrolysis cells

Abstract CO2 electrolysis in solid oxide electrolysis cells (SOECs) holds promise for renewable energy storage and carbon recycling. However, current catalysts used in SOECs show decent electrochemical performance but limited CO2 conversion. Here, in situ exsolution process of the confined RuFe nanoparticles anchored on La0.6Sr0.4Fe0.95Ru0.05O3-δ perovskite (RuFe/LSFRu) was revealed, and SOEC using RuFe/LSFRu as cathode shows a current density of 2.75 A cm−2 and a CO2 conversion of 83.4% for direct CO2 electrolysis. Furthermore, the ethane-intensified SOEC employing RuFe/LSFRu cathode achieves ethane and CO2 conversion of over 95% (CO2/C2H6 = 4) and syngas production of 0.91 L h−1 cm−2 by integrating dry ethane reforming process with the reverse water-gas shift and electrolysis reactions. In situ electrochemical diffuse reflectance infrared Fourier transform spectroscopy and density functional theory calculations reveal that the decomposition of OH* species to produce H2 under the electric ‘driving force’ is crucial to the increase in H2 selectivity and CO2 conversion. These results highlight the superiority of RuFe/LSFRu as bi-functional catalyst for direct and ethane-intensified CO2 electrolysis in SOECs.