Encapsulated Co-Ni alloy boosts high-temperature CO₂ electroreduction.

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis
• Carbon Capture and Utilization

Background:

• Electrochemical carbon dioxide (CO2) reduction is crucial for renewable energy storage and carbon recycling.
• Current high-temperature catalysts in solid oxide electrolysis cells suffer from low energy efficiency (<70%) and limited lifetimes (<200 hours) at high current densities (1 A cm⁻²).
• Operating conditions often involve temperatures of 800°C or higher.

Purpose of the Study:

• To develop a highly efficient and stable catalyst for high-temperature electrochemical CO2 reduction to carbon monoxide (CO).
• To overcome the trade-off between activity and stability in existing catalytic systems.
• To provide a catalyst with potential for industrial applications in carbon recycling.

Main Methods:

• Development of an encapsulated cobalt-nickel (Co-Ni) alloy catalyst.
• Use of samarium-doped ceria (Sm2O3-doped CeO2) as an encapsulation material.
• Testing the catalyst's performance at 800°C and 1 A cm⁻² for CO2-to-CO conversion.

Main Results:

• Achieved 90% energy efficiency and over 2,000 hours of stable operation at 1 A cm⁻² and 800°C.
• Demonstrated ~100% selectivity towards CO and a single-pass yield of 90%.
• The encapsulated structure and optimized alloy composition enhance CO2 adsorption, moderate CO adsorption, and suppress metal agglomeration.

Conclusions:

• The novel encapsulated Co-Ni alloy catalyst significantly improves efficiency and stability for high-temperature CO2 electroreduction.
• The catalyst design strategy effectively addresses limitations of current technologies, offering a promising solution for industrial carbon recycling.
• This work presents a viable pathway for designing robust catalysts for demanding high-temperature chemical transformations.