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Labeling and probing the silica surface using mechanochemistry and 17O NMR spectroscopy

Chen, C.H. ; Mentik-Vigier, F. ; Trébosc, J. ; Goldberga, I. ; Gaveau, P. ; Thomassot, E. ; et al., Chem. Eur. J.

Labeling and probing the silica surface using mechanochemistry and 17O NMR spectroscopy

Chen, C.H. ; Mentik-Vigier, F. ; Trébosc, J. ; Goldberga, I. ; Gaveau, P. ; Thomassot, E. ; et al.

Chemistry A European Journal, 2021

Abstract :

In recent years, there has been increasing interest in developing cost-efficient, fast, and user-friendly 17 O enrichment protocols to help understand the structure and reactivity of materials using 17 O NMR. Here, we show for the first time how ball milling (BM) can be used to selectively and efficiently enrich the surface of fumed silica, which is widely used at the industrial scale. Short milling times (up to 15 min) allowed modulation of the enrichment level (up to ca. 5%) without significantly changing the nature of the material. High-precision 17 O-compositions were measured at different milling times using large-geometry secondary-ion mass spectrometry LG-SIMS. High-resolution 17 O NMR analyses (including at 35.2 T) allowed clear identification of the signals from siloxane (Si-O-Si) and silanols (Si-OH), while DNP analyses, performed using direct 17 O polarization and indirect 17 O 1 H CP excitation, agreed with selective labeling of the surface. Information on the distribution of Si-OH environments at the surface was obtained from 2D 1 H- 17 O D-HMQC correlations. Finally, the surface-labeled silica was reacted with titania and using 17 O DNP, their common interface was probed and Si-O-Ti bonds identified.

Voir en ligne : https://doi.org/10.1002/chem.202101421




publié mardi 22 juin 2021