High electrolysis performance of the SOEC cathode by creating oxygen vacancies to regulate the adsorption energy

Abstract

Solid oxide electrolysis cell (SOEC), as an attractive means of CO₂ emission reduction, possesses the advantages of high efficiency, greenness and flexibility. However, the catalytic performance of cathode materials currently applied to direct CO₂ electrolysis needs to be further improved, which limits its wide application. In this study, a new strategy of using Cu nanoparticles to decorate the Sr_1.9Fe_1.3Cu_0.2Mo_0.4Ti_0.1O_6−δ–Gd_0.2Ce_0.8O_1.9 (Cu@SFCMT–GDC) skeleton to improve the electrolysis performance was proposed. Through the in situ exsolution of Cu nanoparticles, rich metal-oxide heterostructures were constructed, which effectively increased the concentration of oxygen vacancies and thus promoted the electroreduction process of CO₂. At 800 °C and 1.8 V, the maximum electrolytic current density of the cell with Cu@SFCMT–GDC as the cathode reached 1.86 A cm⁻¹. After 210 h of continuous operation, the Cu@SFCMT–GDC did not show any performance degradation. Cu@SFCMT–GDC exhibited outstanding electrochemical performance and durability. Density functional theory (DFT) calculations confirm the promotion of CO₂ reduction reactions by defect chemistry and rich metal-oxide heterostructures. This strategy of constructing heterogeneous interfaces to enhance the cathode electrolysis performance provides new insights into the design of cathode materials for SOEC.