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Updated: Jan 20, 2026
09:00
Electrochemical Detection of Deuterium Kinetic Isotope Effect on Extracellular Electron Transport in Shewanella oneidensis MR-1
Published on: April 16, 2018
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Extraordinarily large kinetic isotope effect on alkene hydrogenation over Rh-based intermetallic compounds
Shinya Furukawa1,2, Pingping Yi1, Yuji Kunisada3
1Institute for Catalysis, Hokkaido University, Sapporo, Japan.
Science and Technology of Advanced Materials
|September 7, 2019
Summary
Rh-based intermetallic compounds show exceptionally high kinetic isotope effects (KIE) in hydrogenation reactions. RhPb2/SiO2 achieved a record KIE of 91, attributed to quantum tunneling during hydrogen adsorption.
Area of Science:
- Heterogeneous Catalysis
- Materials Science
- Physical Chemistry
Background:
- Rh-based intermetallic compounds are promising catalysts for hydrogenation.
- Understanding the mechanism of alkene hydrogenation is crucial for catalyst design.
Purpose of the Study:
- To synthesize and evaluate Rh-based intermetallic compounds for alkene hydrogenation.
- To investigate the kinetic isotope effect (KIE) in hydrogenation reactions.
- To elucidate the origin of unusually high KIE values.
Main Methods:
- Preparation of Rh-based intermetallic compounds supported on silica.
- Testing catalytic activity in alkene hydrogenation using H2 and D2.
- Kinetic studies and density functional theory (DFT) calculations.
Main Results:
- Several Rh-intermetallic compounds exhibited high KIE values in styrene hydrogenation.
- RhPb2/SiO2 demonstrated an unprecedented KIE of 91 at room temperature.
- High KIEs were also observed for phenylacetylene and cyclohexene hydrogenation over RhPb2/SiO2.
- DFT calculations ruled out quantum tunneling in hydrogen diffusion, while kinetic studies identified H2 adsorption as rate-determining.
Conclusions:
- The specific surface structure of RhPb2/SiO2 and adsorbate interaction facilitate quantum tunneling during H2 adsorption.
- This quantum tunneling during the rate-determining H2 adsorption step is responsible for the exceptionally high KIE observed.
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