Solid-state NMR: an eye opener in surface chemistry.

Area of Science:

• Materials Science
• Catalysis
• Spectroscopy

Background:

• Solid-state NMR is crucial for characterizing surface species on amorphous oxide supports, a key step in developing molecularly defined heterogeneous catalysts.
• Understanding the atomic structure of these surface species is vital for establishing structure-property relationships.

Purpose of the Study:

• To highlight the indispensable role of solid-state NMR in determining the atomic structure of surface species on heterogeneous catalysts.
• To showcase advanced NMR techniques and their application in catalyst development.

Main Methods:

• One-dimensional and multi-dimensional NMR analysis for mapping organometallic residues on surfaces.
• Chemical shift anisotropy analysis for detailed structural and dynamic information.
• Density Functional Theory (DFT) calculations combined with high-field and ultrafast 27Al NMR for aluminum species structure determination.
• Dynamic Nuclear Polarization (DNP) for signal enhancement and reduced acquisition times.

Main Results:

• Solid-state NMR effectively maps the structure of organometallic residues, analogous to solution NMR for homogeneous catalysts.
• Chemical shift anisotropy provides detailed structural and dynamic insights into surface species.
• Combined DFT and advanced 27Al NMR successfully determined aluminum species structures.
• DNP significantly reduces NMR acquisition times (up to 10,000x), enabling faster analysis.

Conclusions:

• Solid-state NMR is an indispensable tool for determining structure-property relationships in advanced materials, particularly heterogeneous catalysts.
• Advanced NMR techniques, including DNP, accelerate the rational design and development of novel catalytic materials.