Tungsten oxide-type compound having a new crystalline structure and method for preparing same

Patent metadata

Field	Value
Publication number	US-10450200-B2
Application number	US-201415031353-A
Country	US
Kind code	B2
Filing date	Oct 21, 2014
Priority date	Oct 22, 2013
Publication date	Oct 22, 2019
Grant date	Oct 22, 2019

Abstract

The compound according to the invention is a compound of formula (1) Ax W1-yMOyO3, wherein A is chosen from the group comprising the Li, Na, NH4, K and H cations, and it is characterized in that x and y verify the relationships 0≤x≤1 and 0≤y≤0.5, and in that it has a crystalline structure of the hexagonal type with a base of WO6 octahedra, said structure having tunnels delimited by 6, 4 and 3 of said octahedra and oriented along the axis c.

First claim

The invention claimed is:

1. A compound of formula (1) A x W 1-y Mo y O 3 wherein A is selected from the group consisting of the Li, Na, NH 4 , K and H cations, wherein 0≤x≤1 and 0≤y≤0.5, and wherein the compound exhibits a crystalline structure of hexagonal type which is based on WO 6 octahedra, said structure having tunnels delimited by 6, 4 and 3 of said octahedra and oriented along the axis c.

2. The compound as claimed in claim 1 , wherein 0≤x≤0.2.

3. The compound as claimed in claim 1 , wherein 0.5≤x≤1.

4. The compound as claimed in claim 1 , wherein x and/or y=0.

5. The compound as claimed in claim 1 , wherein the compound exhibits a crystalline structure with lattice parameters a: 10.0(1) Å and c: 3.9(1) Å and space group P6/mmm.

6. The compound as claimed in claim 1 , characterized in that it is composed of particles in the shape of platelets of from 50 to 500 nm in diameter and from 2 to 50 nm thick.

7. A process for preparing a compound as claimed in claim 1 , the process comprising:
(a) contacting an aqueous solution of a salt of W (VI) and, where appropriate, of a salt of Mo(VI), with a reducing agent to form a first medium;
(b) adjusting the pH of the first medium to a value of at most 7 to form a suspension,

wherein a cation A is introduced in one of steps (a) or (b);
(c) maturing the suspension to form a second medium;
(d) heating the second medium to form a third medium;
(e) separating and drying a solid from the third medium to form a compound A x W 1-y Mo y O 3 , wherein x>0;
(f) optionally, eliminating the cation A from the compound A x W 1-y Mo y O 3 to form a compound W 1-y Mo y O 3 .

8. The process as claimed in claim 7 , wherein the aqueous solution in step (a) comprises a salt of tungsten and of the cation A.

9. The process as claimed in claim 7 , wherein step (b) comprises adjusting the pH to a value of at most 2.

10. The process as claimed in claim 7 , wherein step (c) comprises maturing the suspension at a temperature of at most 80° C.

11. The process as claimed in claim 7 , wherein step (d) comprises heating the third medium at a temperature of at least 95° C.

12. The process as claimed in claim 7 , wherein the reducing agent is at least one reducing agent selected from hydrazine, sugars and ascorbates.

13. The process as claimed in claim 7 , wherein A is NH 4 or H and wherein step (f) comprises heating under air.

14. The process as claimed in claim 7 , wherein A is Li, Na, K, NH 4 or H and wherein step (f) comprises an electrochemical oxidation.

15. The process as claimed in claim 7 , wherein A is Li, Na, K or NH 4 and wherein step (f) comprises an ion exchange to replace Li, Na, K or NH 4 with H followed by heating under air or electrochemical oxidation of the compound resulting from the ion exchange.

16. The process as claimed in claim 9 , wherein step (b) comprises adjusting the pH to a value of between 1 and 2.

17. The process as claimed in claim 10 , wherein step (c) comprises maturing the suspension at ambient temperature.

18. The process as claimed in claim 11 , wherein step (d) comprises heating the third medium at a temperature of at least 120° C.

Assignees

• Rhodia Operations
• Centre Nat Rech Scient
• Univ Paris Curie
• Univ Sorbonne

Inventors

• Buissette Valerie
• Le Mercier Thierry
• Besnardiere Julie
• Cassaignon Sophie
• Portehault David
• Wallez Gilles

Classifications

• C01G41/006

  Compounds containing tungsten, with or without oxygen or hydrogen, and containing two or more other elements · CPC title

• C01P2002/60

  Compounds characterised by their crystallite size · CPC title

• C01G41/02 Primary

  Oxides; Hydroxides · CPC title

• C01P2004/20

  extending in two dimensions, e.g. plate-like · CPC title

• C30B7/14

  the crystallising materials being formed by chemical reactions in the solution · CPC title