We show that natural abundance oxygen-17 NMR of solids could be obtained in minutes at a moderate magnetic field strength by using dynamic nuclear polarization (DNP). Electron spin polarization could be transferred either directly to 17O spins or indirectly via 1H spins in inorganic oxides and hydroxides using an oxygen-free solution containing a biradical polarization agent (bTbK). The results open up a powerful method for rapidly acquiring high signal-to-noise ratio solid-state NMR spectra of 17O nuclear spins and to probe sites on or near the surface, without the need for isotope labeling.

see for example:

Dynamic nuclear polarization enhanced natural abundance 17O spectroscopy, F. Blanc, L. Sperrin, D. A. Jefferson, S. Pawsey, M. Rosay, C. P. Grey, J. Am. Chem. Soc. 2013, 135, 2975-2978

Dynamic Nuclear Polarization NMR Spectroscopy Allows High Throughput Characterization of Microporous Organic Polymers, F. Blanc, S. Y. Chong, T. O. McDonald, D. J. Adams, S. Pawsey, M. A. Caporini, A. I. Cooper, J. Am. Chem. Soc. 2013, 135, 15290-15293

Swellable, Water- and Acid-Tolerant Polymer Sponges for Chemoselective Carbon Dioxide Capture, R. T. Woodward, L. A. Stevens, R. Dawson, M. Vijayaraghavan, T. Hasell, I. P. Silverwood, A. V. Ewing, T. Ratvijitvech, J. D. Exley, S. Y. Chong, F. Blanc, D. J. Adams, S. G. Kazarian, C. E. Snape, T. C. Drage, A. I. Cooper, J. Am. Chem. Soc. 2014, 136, 9028-9035

Dynamic Nuclear Polarization NMR of Low Gamma Nuclei: Structural Insights into Hydrated Yttrium-doped BaZrO3, F. Blanc, L. Sperrin, D. Lee, R. Dervişoğlu, Y. Yamazaki, S. M. Haile, G. De Paëpe, C. P. Grey, J. Phys. Chem. Lett. 2014, 5, 2431-2436

Oxygen-17 Dynamic Nuclear Polarisation Enhanced Solid-State NMR Spectroscopy at 18.8 T, N. J. Brownbill, D. Gajan, A. Lesage, L. Emsley, F. Blanc, Chem. Comm. 2017, 53, 2563-2566

Structure Elucidation of Amorphous Photocatalytic Polymers from Dynamic Nuclear Polarization Enhance Solid State NMR, N. J. Brownbill, R. S. Sprick, B. Bonillo, S. Pawsey, F. Aussenac, A. J. Fielding, A. I. Cooper, F. Blanc, Macromolecules 2018, 51, 3088-3096

    17O indirect solid state DNP NMR

1H 17O selective CP (full black lines) and CP QCPMG (green lines) MAS spectra of

(a) 17O-enriched Mg(17OH)2,

(b) natural abundance Mg(OH)2

and (c) natural abundance Ca(OH)2

recorded with microwave irradiation. All the spectra were recorded at 105 K at 9.4 T. Samples were wet with 20 mM bTbK C2Cl4H2 solution. Data were recorded quickly in only 10 min.

     17O direct solid state DNP NMR

(a) Field-dependent direct 17O DNP enhancement profiles of 17O-enriched Mg17O recorded at 105 K. Mg17O was wetted with 20 mM bTbK C2Cl4H2 solution.

(b) Comparison of the 17O spectra of MgO at natural abundance obtained without DNP (red), with direct DNP (black) and with direct DNP and DFS enhanced scheme (green), shown at the DNP(-) position. Eight scans were averaged with a microwave polarization time of 120 s (experimental time = 16 min).