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Development of Heterogeneous Enantioselective Catalysts using Chiral Metal-Organic Frameworks (MOFs)
Published on: January 17, 2020
Characterization of active sites on Rh/SiO(2) model catalysts
Sean M McClure1, M Lundwall, F Yang
1Department of Chemistry, Texas A&M University, PO Box 30012, College Station, TX 77842-3012, USA.
Summary
This study quantifies active Rh surface sites on Rh/SiO(2) catalysts using surface science techniques. Results show good agreement between low and high pressure methods for understanding CO oxidation kinetics.
Area of Science:
- Heterogeneous catalysis
- Surface science
- Materials science
Background:
- Understanding active sites on metal catalysts is crucial for optimizing reactions.
- Rh/SiO(2) is a model system for studying CO oxidation.
- Correlating low-pressure surface characterization with high-pressure reaction kinetics is challenging.
Purpose of the Study:
- To quantify active Rh surface sites on Rh/SiO(2) model catalysts.
- To compare site characterization using in situ scanning tunneling microscopy and infrared reflection absorption spectroscopy with CO desorption and reaction kinetics.
- To evaluate the correlation between low-pressure and elevated-pressure characterization techniques.
Main Methods:
- Preparation of Rh/SiO(2) model catalyst surfaces under ultra-high vacuum.
- In situ characterization using scanning tunneling microscopy (STM) and CO infrared reflection absorption spectroscopy (CO-IRAS).
- Comparison with CO desorption measurements and elevated pressure CO oxidation reaction kinetics.
Main Results:
- Quantified the number and types of active Rh surface sites as a function of Rh particle size.
- Demonstrated good agreement between active site estimates from different characterization methods.
- Validated the utility of low-pressure surface science techniques for understanding high-pressure reaction kinetics.
Conclusions:
- Low-pressure surface science techniques provide reliable estimates of active Rh sites.
- These techniques are valuable for understanding elevated pressure reaction kinetics on model catalysts.
- The study establishes a strong correlation between different methods for characterizing active sites.
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