Presentation Information
[3G12]Probing atomic-level structure of metal oxide surfaces using DNP-enhanced 2D 17O high-resolution and homonuclear correlation NMR experiments
*Hiroki Nagashima1, Julien Trebosc2, Yoshihiro Kon1, Olivier Lafon3, Jean-Paul Amoureux3 (1. The National Institute of Advanced Industrial Science and Technology, Catalytic Chemistry Research Institute, 2. University of Lille, CNRS, IMEC, 3. University of Lille, CNRS, UCCS)
Dynamic nuclear polarization surface-enhanced NMR spectroscopy (DNP-SENS) is a powerful technique for characterizing the surface structure of inorganic nanomaterials. Nevertheless, there is a need to develop DNP-SENS techniques suitable for the observation of half-integer quadrupolar nuclei, which represent 66% of NMR-active isotopes. In this study, we have combined the D-RINEPT transfer with two-dimensional pulse sequences, such as MQMAS scheme or through-space double-quantum-single-quantum homonuclear correlation.These novel DNP-SENS experiments have been leveraged to probe local environment of 17O isotopes near the surface of oxide nanoparticles, such γ-Al2O3, ZnO, ZrO2, CeO2, and (ZnO-ZrO2)/SiO2 catalysts, as well as in alumino-silicate zeolites. We have notably applied these innovative techniques to investigate the chemical selectivity and structural modifications of different approaches used for post-synthetic 17O enrichment: exchange with 17O2 as well as mechanochemistry or slurry using H217O reagent.