Boosting electrochemical CO2 directly electrolysis by tuning the surface oxygen defect of perovskite

The insufficient CO2 adsorption ability on the cathode hinders the development of solid oxide electrolysis cells (SOECs). Regulating the surface oxygen defect of the cathode is an efficient strategy to enhance the electrochemical performance of CO2 electrolysis. Herein, we design oxygen-defect perovskite (La0.5Sr0.5)1-xFe0.9Mn0.1O3-δ oxide by introducing A-site cation deficiency. The effect of A-site deficiency on surface oxygen vacancy and electrocatalytic activity for CO2 reduction is systematically investigated. The relaxation time distribution (DRT) results demonstrate that the enhanced surface oxygen vacancy concentration significantly improves the CO2 adsorption ability, leading to high electrochemical performance for CO2 electrolysis. The single cell with (La0.5Sr0.5)0.9Fe0.9Mn0.1O3-δ cathode attains a current density of 1.1 A cm−2 at 1.6 V and 800 °C. The polarization resistance decreases from 0.6 for (La0.5Sr0.5) Fe0.9Mn0.1O3-δ to 0.25 Ω cm2 for (La0.5Sr0.5)0.9Fe0.9Mn0.1O3-δ cathode at 1.2 V. This work shows that oxygen-defect (La0.5Sr0.5)0.9Fe0.9Mn0.1O3-δ is a potential cathode material for CO2 directly electrolysis.