Periodic Reporting for period 1 - ParaMAS (Paramagnetic Materials Studied by ultra-fast ssNMR Spectroscopy)
Periodo di rendicontazione: 2023-09-01 al 2025-08-31
Materials containing paramagnetic transition-metal ions are crucial for modern technologies involving energy transport, storage, and conversion. While these paramagnetic ions strongly impact material performance, studying their exact local structure and geometry is notoriously difficult, with conventional structural techniques often failing to provide atomic-scale insights.
The ParaMAS project aims to develop and apply new solid-state nuclear magnetic resonance (NMR) methods under ultra-fast magic-angle spinning (MAS), enabling the characterization of nuclei in close proximity to paramagnetic ions. The NMR signals of such nuclei encode very detailed local structural information about the paramagnetic ions, and as such provide the missing atomic-scale structural information needed to link the local environment to the functional properties of energy-relevant materials-
The ParaMAS project aims to develop and apply new solid-state nuclear magnetic resonance (NMR) methods under ultra-fast magic-angle spinning (MAS), enabling the characterization of nuclei in close proximity to paramagnetic ions. The NMR signals of such nuclei encode very detailed local structural information about the paramagnetic ions, and as such provide the missing atomic-scale structural information needed to link the local environment to the functional properties of energy-relevant materials-
During the two-year project, ParaMAS designed and optimized amplitude- and frequency-modulated radiofrequency pulses tailored to allow for broadband inversion at very short irradiation times. This has been instrumental to fully leverage the advantages that are offered by ultra-fast MAS and exploit its full potential in paramagnetic NMR, as well as offsetting the sensitivity penalty due to the small active rotor volumes. This, in combination with MAS at 160 kHz, has amongst others produced the first high-resolution 19F NMR spectrum of F atoms directly bonded to a paramagnetic Fe3+ centre in anti-ferromagnetic FeF3. Furthermore, these pulses were integrated in two-dimensional magic-angle turning experiments, that has allowed us to observe and resolve 1H signals in organo-metallic catalysts, neither of which were possible previously.
In addition to that, the deeper understanding developed for broadband excitation concepts has resulted in exciting new insights in the related field of Pt single-atom catalysts.
In addition to that, the deeper understanding developed for broadband excitation concepts has resulted in exciting new insights in the related field of Pt single-atom catalysts.
Prior to ParaMAS, solid-state NMR studies of nuclei in very close proximity to paramagnetic centres were considered practically impossible. The project demonstrated that high-resolution solid-state NMR data for such sites can be obtained using ultra-fast MAS combined with advanced rf-pulse designs.
This moves the boundaries of detectability in NMR spectroscopy, offering a toolbox for the structural characterization of paramagnetic materials, in particular with high paramagnetic-ion density. The methods will not only impact battery and catalyst research but also benefit a wide range of fields, from solid-state chemistry to materials physics by enabling structural insights into systems previously out of reach.
This moves the boundaries of detectability in NMR spectroscopy, offering a toolbox for the structural characterization of paramagnetic materials, in particular with high paramagnetic-ion density. The methods will not only impact battery and catalyst research but also benefit a wide range of fields, from solid-state chemistry to materials physics by enabling structural insights into systems previously out of reach.