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Surface Enhanced Nuclear Magnetic Resonance Spectroscopy at Solid-Liquid Interfaces Using Overhauser Dynamic Nuclear
Yu Rao1, Domenico Gioffrè2, Marcel Levien1
1Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
Journal of the American Chemical Society
|June 16, 2025
Summary
This study introduces a novel method using exchange-mediated Overhauser effect dynamic nuclear polarization (OE-DNP) to significantly boost Nuclear Magnetic Resonance (NMR) signals from solid surfaces at the solid-liquid interface under ambient conditions.
Area of Science:
- Surface science
- Solid-state NMR spectroscopy
- Organometallic chemistry
Background:
- Detecting solid surface sites at solid-liquid interfaces under ambient conditions is challenging.
- Nuclear Magnetic Resonance (NMR) signal enhancement is crucial for surface characterization.
Purpose of the Study:
- To develop an efficient method for enhancing NMR signals of solid surfaces at the solid-liquid interface at ambient temperature.
- To enable the detection of species at both the surface and in solution for monitoring interfacial chemistry.
Main Methods:
- Utilizing exchange-mediated Overhauser effect dynamic nuclear polarization (OE-DNP).
- Applying the method to 31P NMR signals of triphenylphosphine (PPh3) ligands on Rh(I) surface sites in silica-supported materials.
- Preparing materials via surface organometallic chemistry.
Main Results:
- Achieved efficient DNP enhancements for 31P signals under ambient conditions.
- Observed significant surface enhancement (εsurface = 20-30) and solution enhancement (εsolution up to 50).
- Demonstrated simultaneous signal enhancement at the surface and in solution.
Conclusions:
- The developed OE-DNP approach effectively enhances NMR signals at solid-liquid interfaces.
- This method allows for the detection of species in both surface and solution phases.
- Opens new possibilities for real-time monitoring of surface and interfacial chemistry.
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