Enhanced CO Oxidation on PtO_x Raft Species Synthesized via Citric Acid-Assisted Electrostatic Adsorption

Area of Science:

• Heterogeneous catalysis
• Materials science
• Surface chemistry

Background:

• Platinum-based catalysts are crucial for CO oxidation.
• Catalyst activity is highly sensitive to the nanostructure of platinum species.
• Understanding structure-activity relationships is key for catalyst design.

Purpose of the Study:

• To synthesize and characterize raft-structured PtOx species on CeO2 support (Pt/CeO2-CA).
• To evaluate the catalytic performance of Pt/CeO2-CA for CO oxidation.
• To elucidate the mechanism behind the enhanced activity using characterization and DFT calculations.

Main Methods:

• Citric acid-assisted strong electrostatic adsorption (SEA) for catalyst preparation.
• Catalytic activity testing for CO oxidation, determining T50 and apparent activation energy.
• Advanced catalyst characterization techniques.
• Density Functional Theory (DFT) calculations to study adsorption and reaction mechanisms.

Main Results:

• Pt/CeO2-CA catalysts exhibited a T50 over 120 °C lower than catalysts with Pt single atoms or PtOx clusters.
• The Pt/CeO2-CA catalyst showed the lowest apparent activation energy.
• DFT calculations revealed enhanced CO adsorption on PtOx rafts and favored CO interaction with O* atoms.
• The raft structure mitigates CO poisoning by circumventing competitive adsorption with O2.

Conclusions:

• Raft-structured PtOx on CeO2 represents a highly active catalyst for CO oxidation.
• The enhanced performance is attributed to improved CO adsorption and reaction kinetics on the specific nanostructure.
• This work provides a promising strategy for designing supported noble metal (oxide) nanostructures for improved catalysis.