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Thermally Triggered Redox Flexibility of Pt/CeO2 Cluster Catalyst Against In-Situ Atomic Redispersion
Haofan Lei1, Ningqiang Zhang2, Sunpei Hu1
1Hefei National Research Center for Physical Sciences at the Microscale, Key Laboratory of Strongly-Coupled Quantum Matter Physics of Chinese Academy of Sciences, Key Laboratory of Surface and Interface Chemistry and Energy Catalysis of Anhui Higher Education Institutes, Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui, 230026, P.R. China.
Angewandte Chemie (International Ed. in English)
|May 28, 2025
Summary
We found that platinum (Pt) clusters on cerium dioxide (CeO2) spontaneously disperse into single atoms during CO oxidation, reducing catalyst activity. Thermal aging preserves Pt clusters, enhancing CO oxidation performance.
Area of Science:
- Materials Science
- Catalysis
- Surface Chemistry
Background:
- Supported catalysts can undergo redispersion, where metal sites aggregate into single atoms.
- This process is influenced by metal-support interactions and can decrease catalytic activity.
- Understanding redispersion is crucial for designing stable and active catalysts.
Purpose of the Study:
- To investigate the spontaneous redispersion of platinum (Pt) clusters on cerium dioxide (CeO2) during CO oxidation.
- To identify the stabilizing factors and deactivation mechanisms involved in Pt redispersion.
- To develop a strategy for preserving Pt clusters and enhancing catalytic performance.
Main Methods:
- Utilized CO oxidation as a model reaction to study catalyst behavior.
- Investigated the role of Pt-CeO2 interaction and surface hydroxyls in redispersion.
- Employed high-temperature calcination (800 °C) as a thermal aging strategy.
- Analyzed the structural evolution of Pt species (clusters vs. single atoms).
Main Results:
- Discovered spontaneous redispersion of Pt clusters into single atoms on CeO2, driven by Pt-CeO2 interaction stabilized by hydroxyls.
- Observed catalyst deactivation due to redispersion, leading to inferior catalytic activity.
- Demonstrated that high-temperature calcination removes hydroxyls, preventing redispersion and preserving Pt clusters.
- Showcased triggered Ce3+/Ce4+ redox cycles and enhanced CO adsorption on preserved Pt clusters, leading to superior CO oxidation activity.
Conclusions:
- Surface hydroxyls play a critical role in stabilizing dispersed Pt single atoms, leading to deactivation.
- Thermal aging by high-temperature calcination effectively prevents redispersion by removing hydroxyls.
- Preserving Pt clusters and leveraging interfacial Ce3+ sites for O2 activation and enhanced CO adsorption results in superior catalytic performance for CO oxidation.
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