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

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Solid oxide electrolysis cells (SOECs) are promising for CO2 conversion.
• Current SOECs face challenges with sluggish kinetics and limited durability for CO2 reduction reaction (CO2RR).

Purpose of the Study:

• To develop a novel electrode material for symmetrical SOECs to improve CO2RR performance.
• To investigate the role of medium-entropy perovskites in enhancing CO2RR and oxygen electrocatalysis.

Main Methods:

• Synthesis and characterization of a novel medium-entropy perovskite, Sr2(Fe1.0Ti0.25Cr0.25Mn0.25Mo0.25)O6-δ (SFTCMM).
• Experimental and theoretical analysis of SFTCMM's electronic structure and its effect on CO2RR.
• Performance testing of SFTCMM-based symmetrical SOECs for CO2RR.

Main Results:

• SFTCMM exhibits enhanced metal-O hybridization and reduced O 2p bond center due to configurational entropy.
• Improved oxygen vacancy creation/diffusion and CO2 adsorption/activation were observed.
• SFTCMM-based SOEC achieved a current density of 1.50 A cm-2 at 800 °C, outperforming SFM (1.04 A cm-2).
• Stable CO2RR operation for 160 hours was demonstrated.

Conclusions:

• The medium-entropy SFTCMM perovskite is a highly effective electrode material for symmetrical SOECs in CO2RR.
• Enhanced electronic structure and kinetics contribute to superior performance and durability.
• This work offers a promising pathway for efficient CO2 conversion using SOECs.