Reaction-driven restructuring of Rh-Pd and Pt-Pd core-shell nanoparticles

Area of Science:

• Materials Science
• Catalysis
• Surface Chemistry

Background:

• Bimetallic nanoparticles are crucial in heterogeneous catalysis.
• Metal segregation in nanoparticles can be influenced by reaction environments.
• Understanding nanoparticle restructuring is key to catalyst design.

Purpose of the Study:

• To investigate the in situ structural and compositional changes of Rh(0.5)Pd(0.5) and Pt(0.5)Pd(0.5) nanoparticle catalysts.
• To compare the stability and response of different bimetallic nanoparticle systems under various reaction conditions.
• To explore the tunability of bimetallic nanoparticle structures during catalytic reactions.

Main Methods:

• In situ X-ray photoelectron spectroscopy (XPS) at near-ambient pressure.
• Study of core-shell Rh(0.5)Pd(0.5) and Pt(0.5)Pd(0.5) nanoparticle catalysts.
• Exposure to oxidizing, reducing, and catalytic reaction conditions (NO, O2, CO, H2).

Main Results:

• Rhodium-palladium (Rh(0.5)Pd(0.5)) nanoparticles exhibited significant and reversible changes in composition and chemical state.
• Platinum-palladium (Pt(0.5)Pd(0.5)) nanoparticles showed no substantial segregation of constituent metal atoms.
• Distinct restructuring and chemical responses were observed for the two bimetallic systems under identical conditions.

Conclusions:

• The behavior of bimetallic nanoparticle catalysts is highly dependent on their composition.
• Rhodium-palladium nanoparticles demonstrate dynamic restructuring, offering tunable catalytic properties.
• Platinum-palladium nanoparticles exhibit greater structural stability under the studied conditions.
• These findings underscore the flexibility and tunability of bimetallic nanoparticle structures in catalysis.