Low-Temperature Catalytic NO Reduction with CO by Subnanometric Pt Clusters

Area of Science:

• Heterogeneous catalysis
• Surface science
• Nanomaterials chemistry

Background:

• Subnanometric metal clusters bridge single atoms and nanoparticles, exhibiting unique electronic and geometric properties.
• Understanding the catalytic behavior of these clusters is crucial for designing efficient catalysts.

Purpose of the Study:

• To comparatively study platinum (Pt) catalysts for the CO + NO reaction at low temperatures (140-200 K).
• To elucidate the role of Pt cluster size on catalytic activity and stability.

Main Methods:

• Operando infrared (IR) spectroscopy
• Electronic structure calculations
• Comparative analysis of Pt single atoms, subnanometric clusters, and nanoparticles.

Main Results:

• Single Pt atoms on MCM-22 zeolite are unstable and agglomerate under reaction conditions.
• Pt nanoparticles (∼2 nm) show limited CO oxidation and are susceptible to poisoning by CO and NO.
• Subnanometric Pt clusters facilitate NO dissociation and CO oxidation while resisting poisoning, indicating superior performance.

Conclusions:

• Subnanometric Pt clusters are the key active sites for the CO + NO reaction at low temperatures.
• Catalyst performance is highly dependent on Pt size, with subnanometric clusters offering an optimal balance of activity and stability.
• These findings highlight the potential of subnanometric clusters for low-temperature catalytic applications.