14 November 2022

17O Labeling Reveals Paired Active Sites in Zeolite Catalysts

Left: A zeolite micropore and pair of active sites. Right: The signal-to-noise and spectral resolution in 17O NMR spectra is significantly enhanced at higher magnetic fields. Left: A zeolite micropore and pair of active sites. Right: The signal-to-noise and spectral resolution in 17O NMR spectra is significantly enhanced at higher magnetic fields.

Zeolite catalysts are critical to generating the molecules that provide the building blocks of society’s energy and materials needs. Discerning a clear atomic-level picture of the active sites remains challenging for most current technologies, but here we show that solid-state nuclear magnetic resonance (ssNMR) methods coupled with ultra-high magnetic field instruments, can and has provided extremely useful information for catalyst development.

What did scientists discover?

Crucial details on the structures and proximities of active catalytic sites in zeolite catalysts are revealed by ultra-high-magnetic-field solid-state nuclear magnetic resonance (ssNMR) methods that include enrichment of the catalyst by 17O isotopic substitution.

THE TOOLS THEY USED

This research was conducted in the MagLab 14.1T/600 MHz, 19.6T/830 MHz at the MagLab's NMR Facility and 36-tesla series connected hybrid magnet at DC Field Facility.

Why is this important?

Zeolite catalysts are widely used in modern industrial processes, such as petrochemical refinement and biomass conversion. Economic, environmental, and engineering requirements dictate that fundamental understanding of structure and performance drive new catalyst developments. Recent studies show that active catalytic sites are more complex than previously thought. A phenomenon of great importance is the synergistic effect, where the reactivity of two proximate (nearby) active sites is increased relative to that of two sites separated by a large distance. Ultra-high-magnetic-field 17O ssNMR experiments conducted on a variety of catalyst samples enriched with 17O isotopes revealed potential synergistic site structures. Such information is crucial for the rational design, synthesis, and manufacture of catalysts with improved efficiency and yields.

Who did the research?

Kuizhi Chen,1 Anya Zornes,2 Vy Nguyen,3 Bin Wang,3 Zhehong Gan,1 Steven P. Crossley, and Jeffery L. White2

1National MagLab; 2Oklahoma State University; 3University of Oklahoma

Why did they need the MagLab?

Ultra-high-magnetic-field (UHMF) ssNMR spectroscopy of 27Al and 17O nuclei provides structural details that cannot be obtained from experiments at lower fields, offering an unprecedented combination of high signal and high resolution that is required for these observations. This is made possible by the combination of UHMF ssNMR platforms and state-of-the-art probes available only at the MagLab.

Details for scientists

Funding

This research was funded by the following grants: J. L. White (CHE-1764116 and CHE-1764130); G.S. Boebinger (NSF DMR-1644779)


For more information, contact Robert Schurko.

Details

  • Research Area: Chemistry, Chemistry - Inorganic and Coordination, Chemistry - Materials, Magnet Resonance Technique Development
  • Research Initiatives: Energy,Materials
  • Facility / Program: NMR/MRI
  • Year: 2022
Last modified on 14 November 2022