Highly Efficient CO₂ Electrolysis on Cathodes with Exsolved Alkaline Earth Oxide Nanostructures

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Solid oxide CO2 electrolyzers offer solutions for renewable energy storage and greenhouse gas reduction.
• Key challenges include poor CO2 adsorption and activation on cathode materials at operating temperatures.

Purpose of the Study:

• To develop a novel cathode material for solid oxide CO2 electrolysis with enhanced CO2 adsorption and activation.
• To improve the efficiency and stability of CO2 reduction in electrolyzers.

Main Methods:

• In situ growth of Strontium Oxide (SrO) nanoislands on a perovskite titanate (La, Sr)TiO3+δ cathode surface by controlling nonstoichiometry.
• Characterization of CO2 adsorption and activation mechanisms using Density Functional Theory (DFT) calculations.
• Evaluation of electrolysis performance and current efficiencies at elevated temperatures.

Main Results:

• Successfully tailored the perovskite titanate cathode surface by exsolving SrO nanoislands.
• Demonstrated significantly enhanced CO2 adsorption and activation on the modified cathode surface, stable up to 800 °C.
• DFT calculations revealed CO2 activation through interaction between SrO nanoislands and the defected titanate surface.

Conclusions:

• The novel cathode surface modification strategy leads to highly effective CO2 adsorption and activation.
• The developed solid oxide CO2 electrolyzer exhibits exceptional performance with near 100% current efficiencies.
• This approach presents a promising pathway for efficient CO2 utilization and greenhouse gas mitigation.