Dynamic charge and oxidation state of Pt/CeO₂ single-atom catalysts

Area of Science:

• Materials Science
• Surface Chemistry
• Computational Chemistry

Background:

• Catalytic activity of supported metals is linked to their charge and oxidation state.
• Quantifying charge transfer at metal-support interfaces remains a challenge.

Purpose of the Study:

• To investigate the dynamic nature of metal charge states on oxide supports.
• To elucidate the mechanism of strong metal-support interactions.

Main Methods:

• Density functional theory (DFT) calculations.
• First-principles molecular dynamics simulations.
• Modeling Pt single atoms on CeO2 (100) surfaces.

Main Results:

• Metal charge is not static but exists in dynamically interconnected states.
• Strong metal-support interactions arise from the relative positioning of Ce(4f) and metal levels.
• Phonon-assisted processes involving surface atom displacement facilitate charge transfer.

Conclusions:

• A dynamic model of metal charge states improves understanding of catalytic activity.
• Activated single Pt atoms on ceria exhibit enhanced CO oxidation, addressing the DOE 150°C emissions challenge.
• The observed phenomena extend to other metal-support systems like Ni/TiO2.