Ultra-Fine CeO₂ Particles Triggered Strong Interaction with LaFeO₃ Framework for Total and Preferential CO Oxidation

Area of Science:

• Catalysis
• Materials Science
• Surface Chemistry

Background:

• Strong metal-support interactions (SMSI) are well-understood in metal catalysts.
• Interactions in mixed oxide catalysts are complex and less understood.
• Cerium dioxide (CeO₂) and lanthanum ferrite (LaFeO₃) are key oxygen storage materials.

Purpose of the Study:

• Investigate the interaction between CeO₂ and LaFeO₃ in mixed oxide catalysts.
• Understand the effect of CeO₂ particle size on oxide-oxide interactions.
• Determine how these interactions influence catalytic activity and selectivity for CO oxidation.

Main Methods:

• Tuning the size of CeO₂ particles supported on LaFeO₃.
• Characterizing the oxide-oxide interface and its properties.
• Evaluating catalytic performance for preferential CO oxidation in H₂ feeds.

Main Results:

• Anchoring ultra-fine CeO₂ (<2 nm) on LaFeO₃ creates strong oxide-oxide interactions.
• These interactions generate uncoordinated cations and oxygen vacancies, boosting oxygen mobility and CO oxidation activity.
• Hydrogen spillover is observed, similar to SMSI in precious metal catalysts.
• Surface hydroxyl groups form, and combined with hydrogen spillover, they decrease CO oxidation selectivity.

Conclusions:

• Tuning oxide-oxide interactions is crucial for mixed oxide catalysts.
• A strong interaction between CeO₂ and LaFeO₃ offers improved activity but reduced selectivity.
• Balancing catalytic activity and selectivity requires careful control of component interactions.