In situ electrochemical reconstruction of Sr ₂Fe _1.45Ir _0.05Mo _0.5O _6-δ perovskite cathode for CO ₂ electrolysis in solid oxide electrolysis cells

ABSTRACT

Solid oxide electrolysis cells provide a practical solution for the direct conversion of CO ₂ to other chemicals (i.e. CO), however, an in-depth mechanistic understanding of the dynamic reconstruction of active sites for perovskite cathodes during CO ₂ electrolysis remains a great challenge. Herein, we identify that iridium-doped Sr ₂Fe _1.45Ir _0.05Mo _0.5O _6-δ (SFIrM) perovskite displays a dynamic electrochemical reconstruction feature during CO ₂ electrolysis with abundant exsolution of highly dispersed IrFe alloy nanoparticles on the SFIrM surface. The in situ reconstructed IrFe@SFIrM interfaces deliver a current density of 1.46 A cm ⁻² while maintaining over 99% CO Faradaic efficiency, representing a 25.8% improvement compared with the Sr ₂Fe _1.5Mo _0.5O _6-δ counterpart. In situ electrochemical spectroscopy measurements and density functional theory calculations suggest that the improved CO ₂ electrolysis activity originates from the facilitated formation of carbonate intermediates at the IrFe@SFIrM interfaces. Our work may open the possibility of using an in situ electrochemical poling method for CO ₂ electrolysis in practice.

Abstract

The in situ electrochemical reconstructed IrFe@SFIrM interfaces facilitate the formation of carbonate intermediates and contribute to an enhanced CO ₂ electrolysis performance in solid oxide electrolysis cells.