Boosting catalytic and CO₂ adsorption ability by in situ Cu nanoparticle exsolution for solid oxide electrolysis cell cathode

Solid oxide electrolysis cell (SOEC) is recognized as an effective means to accomplish sustainable development since it is an efficient electrochemical technology for CO₂ emission reduction. However, the electrocatalytic reduction activity of the cathode for CO₂ restricts the development of SOEC. Herein, an A-site deficient perovskite Sr_1·9Fe_1·3Cu_0·2Mo_0·4Ti_0·1O_6-δ (SFCMT) was proposed as cathode material that can in situ exsolve uniform Cu nanoparticles. The exsolution of Cu increases the concentration of oxygen vacancies and provides abundant adsorption sites for CO₂, resulting in excellent electrochemical catalytic capacity. Cu@SFCMT-based single cells exhibit excellent electrolytic performance under pure CO₂, with current densities up to 3.21 A cm⁻² at 1.8 V and 800 °C and interface polarization resistance (Rp) as low as 0.20 Ω cm² at 800 °C. Furthermore, the current density changes slightly after the 140 h stability test at 1.2 V. Cu@SFCMT exhibits outstanding electrochemical activity and durability, making it a viable SOEC cathode material.