<i>In situ</i> electrochemical reconstruction of Sr2Fe1.45Ir0.05Mo0.5O6-δ perovskite cathode for CO2 electrolysis in solid oxide electrolysis cells

Abstract

Solid oxide electrolysis cells provide a practical solution for the direct conversion of CO₂ to other chemicals (i.e. CO), however, an in-depth mechanistic understanding of the dynamic reconstruction of active sites for perovskite cathodes during CO₂ electrolysis remains a great challenge. Herein, we identify that iridium-doped Sr₂Fe_1.45Ir_0.05Mo_0.5O_6-δ (SFIrM) perovskite displays a dynamic electrochemical reconstruction feature during CO₂ electrolysis with abundant exsolution of highly dispersed IrFe alloy nanoparticles on the SFIrM surface. The <i>in situ</i> 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 Sr₂Fe_1.5Mo_0.5O_6-δ counterpart. <i>In situ</i> electrochemical spectroscopy measurements and density functional theory calculations suggest that the improved CO₂ electrolysis activity originates from the facilitated formation of carbonate intermediates at the IrFe@SFIrM interfaces. Our work may open the possibility of using an <i>in situ</i> electrochemical poling method for CO₂ electrolysis in practice.