ja6b08769_si_001.pdf (3.06 MB)
Evidence for Core Oxygen Dynamics and Exchange in Metal Oxide Nanocrystals from In Situ 17O MAS NMR
journal contribution
posted on 2016-11-24, 00:00 authored by Yohan Champouret, Yannick Coppel, Myrtil L. KahnLong-term stability
of the properties of nanocrystals (NCs) is
of paramount importance for any applicative development. However,
these are jeopardized by chemical and structural alterations of the
NCs induced by the environment and the working conditions. Among the
species that alter the NCs properties, water molecules are of tremendous
importance. We used 17O solid-state NMR spectroscopy to
follow this process and the dynamics of O atoms in metal oxide NCs.
Using ZnO as reference material, different chemical environments for
the O atoms are characterized and a dynamic exchange process between
the NCs and the O atoms from water is evidenced. The exchange does
not involve only surface atoms but also ones located deeper inside
the ZnO core of the NCs. Finally, a postsynthesis process based on
watering/drying cycles is proposed that may greatly improve the long-term
stability of metal oxide NCs.