Abstract
A typical type of core-shell polyoxometalates can be obtained through the Keggin-type polyoxometalate-templated growth of a layer of spherical shell structure of {Mo72Fe30}. Small-angle X-ray scattering is used to study the structural features and stability of the core-shell structures in aqueous solutions. Time-resolved small-angle X-ray scattering is applied to monitor the synthetic reactions, and a three-stage formation mechanism is proposed to describe the synthesis of the core-shell polyoxometalates based on the monitoring results. New protocols have been developed by fitting the X-ray data with custom physical models, which provide more convincing, objective, and completed data interpretation. Quasi-elastic and inelastic neutron scattering are used to probe the dynamics of water molecules in the core-shell structures, and two different types of water molecules, the confined and structured water, are observed. These water molecules play an important role in bridging core and shell structures and stabilizing the cluster structures.
Original language | English |
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Pages (from-to) | 2638-2643 |
Number of pages | 6 |
Journal | Journal of the American Chemical Society |
Volume | 138 |
Issue number | 8 |
DOIs | |
State | Published - Mar 2 2016 |
Funding
P.Y. is grateful to the support of Clifford G. Shull Fellowship from Neutron Sciences Directorate of Oak Ridge National Laboratory. The research performed in BL-2 (BASIS) and BL-16B (VISION) at ORNL’s Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, US Department of Energy. The sample preparation and initial SAXS study in the X-ray lab were conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility. Oak Ridge National Laboratory is supported by the Office of Science of the US Department of Energy under Contract No. DE-AC05-00OR22725. The synchrotron-based SAXS study carried out in 12-ID-B and 12-ID-C used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357.