title: Evidence for Core Oxygen Dynamics and Exchange in Metal Oxide Nanocrystals from In Situ17O MAS NMR.
abstract: Long-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 used17O 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.
authors.affiliation: Laboratoire de Chimie de Coordination du CNRS , 205 route de Narbonne, 31077 Toulouse Cedex 04, France.
authors.forename: Yohan
authors.initials: Y
authors.lastname: Champouret
authors.affiliation: Laboratoire de Chimie de Coordination du CNRS , 205 route de Narbonne, 31077 Toulouse Cedex 04, France.
authors.forename: Yannick
authors.initials: Y
authors.lastname: Coppel
authors.affiliation: Laboratoire de Chimie de Coordination du CNRS , 205 route de Narbonne, 31077 Toulouse Cedex 04, France.
authors.forename: Myrtil L
authors.identifier: 0000-0003-3079-5759
authors.initials: ML
authors.lastname: Kahn