Dual-functional engineering of Fe nanoparticles and oxygen vacancies in Sr1.9Fe1.5Mo0.5O6−δ perovskites for high-efficiency CO2/H2O co-electrolysis

Abstract

The development of high-performance perovskite cathodes is critical for advancing carbon-neutral energy technologies through efficient CO₂-to-fuel conversion in solid oxide electrolysis cells (SOECs). In this work, we present a groundbreaking dual-functional engineering strategy that simultaneously achieves in situ exsolution of Fe nanoparticles and oxygen vacancy formation in Sr_2−xFe_1.5Mo_0.5O_6−δ perovskites. By correlating A-site deficiency with tailored reduction protocols, we demonstrate precise control over Fe nanoparticle density and the oxygen vacancy concentration, synergistically addressing the dual bottlenecks of CO₂ activation kinetics and ionic transport limitations. The engineered cathode delivers record-breaking performance: −0.92 A cm⁻² (H₂O electrolysis@800 °C/1.3 V) and −1.58 A cm⁻² (co-electrolysis@800 °C/1.5 V), surpassing that of benchmark perovskites. The dual-modified architecture demonstrates unprecedented durability with 120 h of steam electrolysis and 80 h of co-electrolysis operation at 750 °C/0.5 A cm⁻². This work establishes a materials design paradigm that directly bridges atomic-scale defect engineering with macroscale energy conversion efficiency, offering a scalable pathway for transforming industrial CO₂ emissions into renewable fuels.