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Fully Dispersed Rh Ensemble Catalyst To Enhance Low-Temperature Activity.
Hojin Jeong1, Geonhee Lee2, Beom-Sik Kim1
1Department of Chemical and Biomolecular Engineering , Korea Advanced Institute of Science and Technology , Daejeon 34141 , South Korea.
Journal of the American Chemical Society
|July 6, 2018
Summary
Researchers developed highly dispersed Rhodium (Rh) catalysts that outperform single-atom catalysts (SACs) for low-temperature oxidation reactions. These catalysts show enhanced atom-efficiency and activity, crucial for industrial applications.
Area of Science:
- Heterogeneous catalysis
- Materials science
- Surface chemistry
Background:
- Precious metal catalysts are vital but costly; minimizing their use is a key goal.
- Single-atom catalysts (SACs) offer maximum atom efficiency but lack ensemble sites for certain reactions.
- Reactions requiring multiple adjacent metal atoms cannot be catalyzed by SACs.
Purpose of the Study:
- To develop a highly dispersed Rhodium (Rh) catalyst with ensemble sites.
- To evaluate the catalytic performance of the new Rh catalyst compared to SACs.
- To understand the mechanism of catalyst formation and its impact on activity.
Main Methods:
- Hydrothermal treatment of 2 wt% Rh/CeO2 at 750 °C for 25 hours.
- Characterization of catalyst dispersion and Rh atom aggregation state (ENS vs. SAC).
- Testing catalytic activity in low-temperature oxidation of CO, C3H6, and C3H8, including simultaneous reactions.
Main Results:
- Achieved nearly 100% dispersion with non-isolated Rh atoms (ENS) after hydrothermal treatment.
- ENS catalysts effectively catalyzed C3H6 and C3H8 oxidation, unlike Rh SACs.
- ENS catalysts showed significantly lower light-off temperatures (T20) in simultaneous CO, C3H6, and C3H8 oxidation compared to SACs (100 °C vs. 180 °C for CO oxidation).
Conclusions:
- The developed ENS Rh catalyst exhibits superior low-temperature oxidation activity compared to SACs.
- Hydrothermal treatment facilitates Rh atom detachment and prevents reaggregation via surface hydroxyl groups.
- This fully dispersed ENS catalyst offers high atom-efficiency and enhanced catalytic performance for specific reactions.
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