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Title: Static and Dynamical Structural Investigations of Metal-Oxide Nanocrystals by Powder X-ray Diffraction: Colloidal Tungsten Oxide as a Case Study

In this study, we have developed a general X-ray powder diffraction (XPD) methodology for the simultaneous structural and compositional characterization of inorganic nanomaterials. The approach is validated on colloidal tungsten oxide nanocrystals (WO 3-x NCs), as a model polymorphic nanoscale material system. Rod-shaped WO 3-x NCs with different crystal structure and stoichiometry are comparatively investigated under an inert atmosphere and after prolonged air exposure. An initial structural model for the as-synthesized NCs is preliminarily identified by means of Rietveld analysis against several reference crystal phases, followed by atomic pair distribution function (PDF) refinement of the best-matching candidates (static analysis). Subtle stoichiometry deviations from the corresponding bulk standards are revealed. NCs exposed to air at room temperature are monitored by XPD measurements at scheduled time intervals. The static PDF analysis is complemented with an investigation into the evolution of the WO 3-x NC structure, performed by applying the modulation enhanced diffraction technique to the whole time series of XPD profiles (dynamical analysis). Prolonged contact with ambient air is found to cause an appreciable increase in the static disorder of the O atoms in the WO 3-x NC lattice, rather than a variation in stoichiometry. Finally, the time behavior of such structuralmore » change is identified on the basis of multivariate analysis.« less
Authors:
ORCiD logo [1] ;  [1] ; ORCiD logo [1] ; ORCiD logo [2] ; ORCiD logo [3] ;  [4] ; ORCiD logo [5] ; ORCiD logo [6] ; ORCiD logo [1]
  1. IC CNR-Institute of Crystallography, Bari (Italy)
  2. Universita del Salento, Lecce (Italy). Dipartimento di Matematica e Fisica E. De Giorgi"; Center for Biomolecular Nanotechnologies@UNILE Istituto Italiano di Tecnologia, Arnesano (Italy); CNR NANOTEC ”Institute of Nanotechnology c/o Campus Ecotekne, University of Salento, Lecce (Italy)
  3. Brookhaven National Lab. (BNL), Upton, NY (United States). Chemistry Department
  4. Brookhaven National Lab. (BNL), Upton, NY (United States). Photon Sciences
  5. Center for Biomolecular Nanotechnologies at UNILE, Istituto Italiano di Tecnologia, Arnesano (Italy)
  6. Universita del Salento, Lecce (Italy). Dipartimento di Matematica e Fisica E. De Giorgi; CNR NANOTEC Institute of Nanotechnology c/o Campus Ecotekne, University of Salento, Lecce (Italy)
Publication Date:
Report Number(s):
BNL-112193-2016-JA
Journal ID: ISSN 1439-4235; R&D Project: CO009; KC0302010
Grant/Contract Number:
SC0012704; AC02-98CH10886; RBAP114AMK_006; PON02_00563_3316357
Type:
Accepted Manuscript
Journal Name:
ChemPhysChem
Additional Journal Information:
Journal Volume: 17; Journal Issue: 5; Journal ID: ISSN 1439-4235
Publisher:
ChemPubSoc Europe
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY; colloids; nanoparticles; oxides; pair distribution; function; X-ray diffraction
OSTI Identifier:
1336039
Alternate Identifier(s):
OSTI ID: 1401172