Preparation of tungsten oxide

• US 20050025700A1
• Filed: 07/28/2003
• Published: 02/03/2005
• Est. Priority Date: 07/28/2003
• Status: Active Grant

• Current Assignee: Los Alamos National Security LLC (Government of the United States of America)
• Original Assignee: Los Alamos National Security LLC (Government of the United States of America)
• Inventors: Jorgensen, Betty S., Son, Steven F., Dye, Robert C., Perry, W. Lee, Bulian, Christopher J.
• Granted Patent: US 7,591,984 B2
• Time in Patent Office: Days
• US Class Current: 423/606
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C01G 41/00 Compounds of tungsten
• CPC Class Codes: C01G 41/02 Oxides; Hydroxides
• CPC Class Codes: C01P 2002/72 by d-values or two theta-values, e.g. as X-ray diagram
• CPC Class Codes: C01P 2002/74 by peak-intensities or a ratio thereof only
• CPC Class Codes: C01P 2002/76 by a space-group or by other symmetry indications
• CPC Class Codes: C01P 2002/82 by IR- or Raman-data
• CPC Class Codes: C01P 2004/03 obtained by SEM
• CPC Class Codes: C01P 2004/20 extending in two dimensions, e.g. plate-like
• CPC Class Codes: C01P 2004/64 Nanometer sized, i.e. from 1-100 nanometer
• CPC Class Codes: C01P 2006/12 Surface area

Abstract

Tungsten trioxide hydrate (WO₃.H₂0) was prepared from a precursor solution of ammonium paratungstate in concentrated aqueous hydrochloric acid. The precursor solution was rapidly added to water, resulting in the crash precipitation of a yellow white powder identified as WO₃.H₂0 nanosized platelets by x-ray diffraction and scanning electron microscopy. Annealing of the powder at 200° C. provided cubic phase WO₃ nanopowder, and at 400° C. provided WO₃ nanopowder as a mixture of monoclinic and orthorhombic phases.

Claims

1. A solution comprising a combination of ammonium paratungstate and hydrochloric acid.

3. The solution of claim 1 wherein said hydrochloric acid comprises an aqueous solution of about 35-38 weight percent of hydrochloric acid.

2. A solution prepared by combining ammonium paratungstate with hydrochloric acid.

4. A method for preparing WO₃.H₂0 comprising preparing a precursor solution comprising a combination of ammonium paratungstate and hydrochloric acid and combining the precursor solution with water to form a precipitate, and isolating the precipitate.

5. A method for preparing anhydrous WO₃ nanopowder comprising preparing a precursor solution comprising ammonium paratungstate and hydrochloric acid, combining the precursor solution with water to form a precipitate, isolating the precipitate, and heating the precipitate to form the anhydrous WO₃ nanopowder.

6. The method of claim 5, wherein the isolated precipitate is heated at a temperature of from about 200°

C. to about 400°

C. to form the WO₃ nanopowder.

7. A method for preparing WO₂ comprising preparing a precursor solution comprising ammonium paratungstate and hydrochloric acid, combining the precursor solution with water to form a precipitate, isolating the precipitate, and heating the precipitate to form the anhydrous WO₃ nanopowder, and reacting the anhydrous WO₃ nanopowder with hydrogen gas to form WO₂.

8. Tungsten trioxide hydrate (WO₃.H₂0) nanosized particles prepared by combining water with a precursor solution comprising a combination of ammonium paratungstate and hydrochloric acid

9. Tungsten trioxide hydrate (WO₃.H₂0) nanosized particles having a platelet morphology.