Thermally stable Pd/CeO₂@SiO₂ with a core-shell structure for catalytic lean methane combustion

Area of Science:

• Catalysis
• Materials Science
• Environmental Chemistry

Background:

• Noble metal catalysts show high activity for lean methane (CH₄) combustion.
• Nanoparticle catalysts face deactivation via migration and aggregation due to high surface energy.

Purpose of the Study:

• To design and synthesize a thermally stable core-shell catalyst for enhanced lean CH₄ combustion.
• To improve the deactivation resistance of noble metal catalysts.

Main Methods:

• Synthesis of a Pd/CeO₂ core encapsulated within a SiO₂ shell (Pd/CeO₂@SiO₂).
• Characterization using various techniques to confirm structure and stability.
• Catalytic activity testing for lean CH₄ combustion.

Main Results:

• Successful synthesis of Pd/CeO₂@SiO₂ with enhanced thermal stability.
• Pd/CeO₂@SiO₂ achieved 90% CH₄ conversion at 385 °C, outperforming Pd/CeO₂ at 440 °C after multiple runs.
• The core-shell structure limited Pd nanoparticle migration and aggregation.

Conclusions:

• The Pd/CeO₂@SiO₂ core-shell catalyst demonstrates superior thermal stability and catalytic performance for lean CH₄ combustion.
• Enhanced metal-support interactions and protection by the SiO₂ shell contribute to improved catalyst durability and activity.
• The catalyst promotes the formation of Pd-Ce-O solid solutions and active oxygen species, boosting redox capacity.