Defect-Engineered LaFeO₃ Stabilizing Oxidized Pt Single-Atom Sites for Low-Temperature CO Oxidation.

Area of Science:

• Materials Science
• Catalysis
• Surface Chemistry

Background:

• Platinum single-atom catalysts (SACs) face a trade-off between activity and stability in oxidation reactions.
• High-coordination sites are stable but inactive; low-coordination sites are active but unstable.
• Overoxidation and aggregation limit the practical application of SACs.

Purpose of the Study:

• To develop a defect-engineering strategy to overcome the activity-stability dilemma in platinum SACs.
• To anchor oxidized platinum single atoms onto a vacancy-engineered perovskite support (v-LaFeO3).
• To enhance catalytic performance for oxidation reactions.

Main Methods:

• Defect engineering of LaFeO3 perovskite by introducing La-vacancies.
• Anchoring oxidized platinum single atoms (Pt4+) onto the v-LaFeO3 support.
• Characterization using structural analysis and in situ experiments.
• Density Functional Theory (DFT) calculations to verify structure and mechanism.

Main Results:

• The v-LaFeO3 support enhances lattice oxygen mobility and preserves structural integrity.
• Anchored Pt single atoms exhibit optimized coordination and a high oxidation state (Pt4+).
• The catalyst demonstrates high and stable activity for CO oxidation without reduction pretreatment.
• Vacancies modulate the interfacial electronic structure, activating lattice oxygen and accelerating O2 activation.

Conclusions:

• Precise control of support defects can concurrently optimize electronic states and stability of SACs.
• This defect-engineering strategy offers a generalized paradigm for designing robust oxidation catalysts.
• The developed catalyst shows promise for long-term, high-temperature oxidation reactions.