Atomistic Insights into Medium-Entropy Perovskites for Efficient and Robust CO2 Electrolysis

Solid oxide electrolysis cells (SOECs) show great promise in converting CO2 to valuable products. However, their practicality for the CO2 reduction reaction (CO2RR) is restricted by sluggish kinetics and limited durability. Herein, we propose a novel medium-entropy perovskite, Sr-2(Fe(1.0)Ti(0.25)Cr(0.25)Mn(0.2)5Mo(0.25))O6-delta (SFTCMM), as a potential electrode material for symmetrical SOEC toward CO2RR. Experimental and theoretical results unveil that the configuration entropy of SFTCMM perovskites contributes to the strengthened metal 3d-O 2p hybridization and the reduced O 2p bond center. This variation of electronic structure benefits oxygen vacancy creation and diffusion as well as CO2 adsorption and activation and ultimately accelerates CO2RR and oxygen electrocatalysis kinetics. Notably, the SFTCMM-based symmetrical SOEC delivers an excellent current density of 1.50 A cm(-2) at 800 degrees C and 1.5 V, surpassing the prototype Sr2Fe1.5Mo0.5O6-delta (SFM, 1.04 A cm(-2)) and most of the state-of-the-art electrodes for symmetrical SOECs. Moreover, the SFTCMM-based symmetrical SOEC demonstrates stable CO2RR operation for 160 h.

Automated summary

Solid oxide electrolysis cells (SOECs) have great potential for CO2 reduction reactions (CO2RR), but their practicality is limited by slow kinetics and durability. A novel medium-entropy perovskite, Sr-2(Fe(1.0)Ti(0.25)Cr(0.25)Mn(0.2)5Mo(0.25))O6-delta (SFTCMM), is proposed as a potential electrode material for symmetrical SOECs, which shows improved performance in CO2RR kinetics and stability.