Deactivation of Single-Atom Catalysts by Nanoparticles

Area of Science:

• Catalysis
• Materials Science
• Nanotechnology

Background:

• Single-atom catalysts (SACs) offer high atomic efficiency and precise catalytic activity due to isolated metal centers.
• However, SACs are dynamic under reaction conditions, challenging their stability.

Purpose of the Study:

• To challenge the view of SACs and nanoparticles (NPs) as distinct systems.
• To propose that NPs can act as catalytic poisonants for SACs by trapping active atoms.
• To highlight the dynamic evolution of SACs and their aggregation into NPs as a key limitation.

Main Methods:

• Review of mechanistic studies, thermodynamic data, and experimental observations.
• Analysis across various reaction classes: hydrogenation, oxidation, and cross-coupling.

Main Results:

• SACs can aggregate into NPs, leading to loss of activity and selectivity.
• This transformation represents a significant deactivation pathway, not just a side process.
• NPs may poison SACs by trapping active single metal atoms.

Conclusions:

• The SAC-NP relationship is a dynamic continuum, not a dichotomy.
• Stabilizing isolated active sites is essential for next-generation catalysts.
• Strategies to suppress NP formation are critical for catalyst stability and utility.