Single-Atom Rh on High-Index CeO₂ Facet for Highly Enhanced Catalytic CO Oxidation

Area of Science:

• Materials Science
• Catalysis
• Surface Chemistry

Background:

• Noble metal nanoparticles on reducible oxides are active oxidation catalysts but suffer from deactivation via atom migration.
• Single-atom catalysts offer stability but often exhibit limited activity due to ionized surface states.

Purpose of the Study:

• To develop highly active and durable rhodium (Rh) single-atom catalysts that overcome the limitations of both nanoparticle and traditional single-atom catalysts.
• To investigate a novel synthesis method for creating stable and active single-atom catalysts on ceria (CeO2) supports.

Main Methods:

• A "wrap-bake-peel" synthesis strategy was employed, utilizing a pre-coated SiO2 layer.
• The process involved supporting rhodium (Rh) single atoms on ceria (CeO2) with exposed high-index {210} facets.
• Characterization focused on the electronic structure and oxygen vacancy generation.

Main Results:

• The SiO2 layer protected the CeO2 support from sintering and facilitated electron donation, weakening the Ce-O bond.
• Highly loaded Rh single atoms were successfully dispersed on CeO2 {210} facets, creating unique electronic structures.
• Enhanced oxygen vacancy generation and the deposition of electropositive Rh single atoms led to significantly improved catalytic performance in CO oxidation.

Conclusions:

• The "wrap-bake-peel" method successfully synthesized highly active and durable Rh single-atom catalysts.
• The unique electronic properties of CeO2 {210} facets, combined with Rh single atoms, are key to the enhanced catalytic activity.
• This approach offers a promising strategy for designing advanced single-atom catalysts for oxidation reactions.