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

Yuxiang Shen; Tianfu Liu; Rongtan Li; Houfu Lv; Na Ta; Xiaomin Zhang; Yuefeng Song; Qingxue Liu; Weicheng Feng; Guoxiong Wang; Xinhe Bao

doi:10.1093/nsr/nwad078

In situ electrochemical reconstruction of Sr₂Fe_1.45Ir_0.05Mo_0.5O_6-δ perovskite cathode for CO₂ electrolysis in solid oxide electrolysis cells

Natl Sci Rev. 2023 Mar 20;10(9):nwad078. doi: 10.1093/nsr/nwad078. eCollection 2023 Sep.

Authors

Yuxiang Shen^{1

2}, Tianfu Liu¹, Rongtan Li^{1

2}, Houfu Lv¹, Na Ta¹, Xiaomin Zhang¹, Yuefeng Song¹, Qingxue Liu^{1

2}, Weicheng Feng^{1

2}, Guoxiong Wang¹, Xinhe Bao¹

Affiliations

¹ State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
² University of Chinese Academy of Sciences, Beijing 100049, China.

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 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 Sr₂Fe_1.5Mo_0.5O_6-δ counterpart. In situ 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 in situ electrochemical poling method for CO₂ electrolysis in practice.

Keywords: CO2 electrolysis; carbonate intermediates; in situ electrochemical reconstruction; metal/perovskite interface; solid oxide electrolysis cell.