Ultralow-Temperature Redispersion of Platinum Nanoparticle Catalysts

Area of Science:

• Materials Science
• Catalysis Science
• Surface Chemistry

Background:

• Catalyst deactivation via sintering necessitates redispersion for activity restoration.
• Conventional redispersion methods use high temperatures or contaminants, degrading catalyst integrity.
• Developing energy-efficient and non-contaminating redispersion techniques is crucial for practical applications.

Purpose of the Study:

• To introduce and investigate a novel, low-temperature redispersion method for Pt/CeO2 catalysts.
• To elucidate the mechanism behind effective redispersion using nitrogen oxide (NO) treatment.
• To demonstrate the broader applicability of this ultralow-temperature redispersion technique.

Main Methods:

• In situ transmission electron microscopy (TEM) for visualizing redispersion dynamics.
• Density functional theory (DFT) calculations to confirm experimental observations.
• Comparative analysis of NO and O2 treatments at low temperatures (200°C).

Main Results:

• Highly dispersed Pt/CeO2 achieved via NO treatment at 200°C.
• NO treatment promotes more effective Pt redispersion on CeO2(100) compared to O2.
• NO treatment forms highly mobile two-coordinated Pt species, while O2 forms less mobile four-coordinated species.

Conclusions:

• Ultralow-temperature redispersion of Pt/CeO2 is achievable using NO treatment.
• The enhanced mobility of NO-induced Pt species drives efficient low-temperature redispersion.
• This method offers an energy-efficient, halogen-free alternative for catalyst regeneration applicable to various systems.