Highly CO2RR activity and electrochemical performance of A-site deficient symmetrical electrode materials (La0.6Sr0.4)1−xFe0.8Ni0.2O3-δ for CO2 electrolysis

A-site deficient (La0.6Sr0.4)1−xFe0.8Ni0.2O3-δ (x = 0, 0.05, 0.1) perovskite oxide materials (LSFN100, LSFN95, and LSFN90) are evaluated as symmetrical electrode materials for CO2 electrolysis. All three perovskite oxides display pure cubic perovskite structure. The introduction of A-site deficiency results in greater tendency of in-situ exsolution and stronger CO2 adsorption capacity, which are verified by temperature-programmed reduction of H2 and temperature-programmed desorption of CO2. Furthermore, the current densities with LSNF90 symmetrical cell are 1.72, 1.18 and 0.72 A·cm−2 under the applied voltage of 1.8 V at 850, 800 and 750 °C to electrolysis CO2, respectively. Low polarization resistance of 0.186, 0.267 and 0.454 Ω·cm2 is also observed under open circuit conditions at 850, 800 and 750 °C, respectively. A-site deficiency of perovskite materials reduces the activation energy of oxygen evolution reaction (OER) and carbon dioxide reduction reaction (CO2RR). Symmetrical cell with LSFN90 electrode shows good electrochemical performance and long-term stability for CO2 electrolysis.