One-dimensional WO{sub 3} and its hydrate: One-step synthesis, structural and spectroscopic characterization

Journal Article · Sun Jan 15 00:00:00 EST 2012 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2011.11.001· OSTI ID:21612879

Galeckas, Augustinas ^[1]; Rauwel, Protima ^[2]; Norby, Truls ^[3]

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1. Department of Physics, University of Oslo, Centre for Materials Science and Nanotechnology, P.O. Box 1048 Blindern, NO-0316 Oslo (Norway)
2. Centre for Materials Science and Nanotechnology, University of Oslo, P.O. Box 1126 Blindern, NO-0318 Oslo (Norway)
3. Department of Chemistry, University of Oslo, Centre for Materials Science and Nanotechnology, FERMiO, Gaustadalleen 21, NO-0349 Oslo (Norway)

We report on a one-step hydrothermal growth of one-dimensional (1D) WO{sub 3} nanostructures, using urea as 1D growth-directing agent and a precursor free of metals other than tungsten. By decreasing the pH of the starting solution, the size of the nanostructures was reduced significantly, this development being accompanied by the realization of phase pure hexagonal WO{sub 3} nanorods (elimination of monoclinic impurity phase) and a red shift in optical absorption edge. Surface analyses indicated the presence of reduced tungsten species in the WO{sub 3} nanostructures, which increased two-fold in a hydrated WO{sub 3} phase obtained with further decrease in pH. We suggest that oxygen vacancies are responsible for this defect state in WO{sub 3}, while protons are responsible or contribute significantly to the same in the hydrated phase. - Graphical abstract: The figure illustrates the role of pH in morphological and absorption edge evolution of WO{sub 3} (hydrate) as well as the variation in the concentration of defect electrons between anhydrous and hydrated WO{sub 3}. Highlights: Black-Right-Pointing-Pointer WO{sub 3} nanorods prepared in a one step procedure. Black-Right-Pointing-Pointer HCl (aq) enables phase pure WO{sub 3} nanorods. Black-Right-Pointing-Pointer HCl (aq) induces significant reduction in dimension of and red shift in absorption edge of nanorods. Black-Right-Pointing-Pointer W{sup 5+} detected in hydrothermal WO{sub 3} phase, the concentration of which increases in the hydrated phase. Black-Right-Pointing-Pointer W{sup 5+} from the two phases due to different positive defects.

• OSTI ID: 21612879
• Journal Information: Journal of Solid State Chemistry, Vol. 185; Other Information: DOI: 10.1016/j.jssc.2011.11.001; PII: S0022-4596(11)00594-9; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ABSORPTION
DEFECTS
HYDROCHLORIC ACID
IMPURITIES
MONOCLINIC LATTICES
NANOSTRUCTURES
PROTONS
SURFACES
SYNTHESIS
TUNGSTATES
TUNGSTEN
TUNGSTEN IONS
TUNGSTEN OXIDES
BARYONS
CHALCOGENIDES
CHARGED PARTICLES
CHLORINE COMPOUNDS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
ELEMENTARY PARTICLES
ELEMENTS
FERMIONS
HADRONS
HALOGEN COMPOUNDS
HYDROGEN COMPOUNDS
INORGANIC ACIDS
INORGANIC COMPOUNDS
IONS
METALS
NUCLEONS
OXIDES
OXYGEN COMPOUNDS
REFRACTORY METAL COMPOUNDS
REFRACTORY METALS
SORPTION
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
TUNGSTEN COMPOUNDS