Two-fold improvement in chemical adsorption ability to achieve effective carbon dioxide electrolysis

A strategy of regulating the basicity of perovskite oxygen ions by cation doping is proposed to design cathode materials with high catalytic activity for solid oxide electrolysis cells (SOECs). Specifically, a series of Sr₂Fe_1.5-xZr_xMo_0.5O_6−δ (SFZxM) perovskites are developed and characterized for its electrocatalytic activity and oxygen ions basicity to investigate the effect on electrochemical performance. The experimental results show that the single cell prepared with the Sr₂Fe_1.3Zr_0.2Mo_0.5O_6−δ (SFZ2M) cathode reaches a current density of 1.85 A cm⁻² at 1.8 V and 800 °C and exhibits good stability over 120 h under CO₂ atmosphere. Combined with first-principles calculations, it is further confirmed that the introduction of low-electronegativity ions can improve the oxygen ions basicity and also increase the oxygen vacancy concentration of the cathode, thereby realizing the improvement of electrochemical performance. Thus, this strategy provides new insights into designing electrodes for direct CO₂ electrolysis as well as other electrochemical catalysis.