High-pressure magic angle spinning nuclear magnetic resonance.

Area of Science:

• Solid-state Nuclear Magnetic Resonance (NMR) Spectroscopy
• Materials Science
• Geochemistry

Background:

• High-pressure magic angle spinning (MAS) NMR is crucial for studying reactions under extreme conditions.
• Developing reusable high-pressure MAS rotors presents significant technical challenges.
• Existing methods lack the capability for sustained in situ high-pressure NMR analysis.

Purpose of the Study:

• To develop and validate a novel reusable high-pressure MAS NMR capability.
• To overcome the technical hurdles in designing high-pressure MAS rotors.
• To demonstrate the system's utility for in situ studies of geological processes.

Main Methods:

• Design and fabrication of a reusable high-pressure MAS rotor using modified ceramic cylinders.
• Development of a specialized loading/reaction chamber for in situ sealing and re-opening.
• Implementation of a MAS probe with a localized RF coil for signal suppression.
• Achieving and sustaining internal pressures exceeding 150 bars for 72 hours.

Main Results:

• Successful development of a reusable high-pressure MAS rotor system.
• Demonstrated ability to maintain high pressures (>150 bar) with minimal loss over 72 hours.
• Successful in situ (13)C MAS NMR studies of mineral carbonation (forsterite with supercritical CO2 and H2O at 150 bar, 50°C).

Conclusions:

• The new high-pressure MAS NMR system is effective for in situ analysis of high-pressure reactions.
• The technology is relevant for investigating mineral carbonation and geological CO2 sequestration.
• This advancement opens new avenues for solid-state NMR research under extreme conditions.