Process for producing a metal oxide powder

Patent metadata

Field	Value
Publication number	US-10889507-B2
Application number	US-201716075034-A
Country	US
Kind code	B2
Filing date	Feb 6, 2017
Priority date	Feb 5, 2016
Publication date	Jan 12, 2021
Grant date	Jan 12, 2021

Abstract

A process for producing a metal oxide powder comprising: providing a precursor solution or dispersion containing a metal complex; spraying the precursor solution on to a heated substrate in the presence of water, thereby depositing material on the substrate; drying the deposited material; and removing the deposited material from the substrate to produce the metal oxide powder.

First claim

The invention claimed is:

1. A process for producing a metal oxide powder comprising of one of a metal (IV) oxide powder (MO 2 where M is a metal) and a metal oxide powder comprising of a metal (III) oxide film (M 2 O 3 where M is a metal),
the process comprising:
providing one of a precursor solution and a dispersion containing a metal (IV) complex or a metal (III) complex;
spraying the precursor solution or dispersion on to a heated substrate in the presence of water, thereby depositing material on the substrate;
drying the deposited material;
cooling the deposited material on the substrate at a controlled cooling rate of at least 10° C./min; and
removing the deposited material from the substrate to produce the metal oxide powder,

wherein:
the metal (M) is vanadium, molybdenum, tungsten, germanium or manganese; and
the spraying, drying and cooling steps are carried out in at least one of a protective or inert atmosphere.

2. A process according to claim 1 , wherein the precursor solution or the dispersion is selected from: an aqueous solution; the concentration of the precursor solution or dispersion is up to 0.1M; and the concentration of the metal (IV) complex or the metal (III) complex in the precursor solution is up to 0.1M.

3. A process according to claim 1 , wherein the metal is selected from one of:
(i) the metal is vanadium and the metal complex is vanadyl acetylacetonate;
(ii) the metal is vanadium and the metal complex is vanadyl oxalate;
(iii) the metal is molybdenum and the metal complex is molybdenyl acetylacetonate; and
(iv) the metal is molybdenum and the metal complex is molybdenyl oxalate or a suitable molybdenum (IV) complex.

4. A process according to claim 1 , wherein the oxidation state of the metal is the same in the metal complex as it is in the metal oxide powder.

5. A process according to claim 1 , wherein the precursor solution or dispersion comprises one or more further metals as dopants.

6. A process according claim 1 , wherein the precursor solution or dispersion is sprayed on to the heated substrate with the aid of a carrier gas optionally wherein the carrier gas is sprayed at a rate of up to 60 ml/min.

7. A process according to claim 1 , wherein the precursor solution or dispersion is sprayed on to the heated substrate at a rate of up to 5 ml/min.

8. A process according to claim 1 , wherein the substrate is heated to a temperature selected from one of:
(i) at least 300° C.;
(ii) at least 400° C.;
(iii) at least 450° C.; and
(iv) up to 550° C.

9. A process according to claim 1 , wherein drying the deposited material comprises the steps of maintaining the substrate at a predetermined drying temperature for a predetermined drying time, wherein the predetermined drying temperature is selected from one of:
(i) at least 300° C.;
(ii) at least 400° C.;
(iii) at least 450° C.; and
(iv) up to 550° C.; and wherein the predetermined drying time is selected from:
(a) at least 5 minutes; and
(b) up to 60 minutes.

10. A process according to claim 1 comprising one of heat treating, and annealing, the deposited material, wherein the heat treating is carried out in one of the protective or inert atmosphere.

11. A process according to claim 1 , wherein the steps of spraying the precursor solution or dispersion on to a heated substrate in the presence of water, thereby depositing material on the substrate and drying the deposited material are repeated one or more times.

12. A process according to claim 1 , wherein the precursor solution has a pH which is selected from one of: at least 5 and up to 9.

13. A process according to claim 1 , wherein the deposited material is removed from the substrate by any suitable non-chemical, non-thermal means selected from the group consisting of scraping the deposited material from the substrate, tipping the substrate, inverting the substrate, and shaking the substrate.

14. A process according to claim 1 , wherein the process comprises a step of further processing the deposited material removed from the substrate.

15. A process according to claim 1 , wherein the substrate comprises a glass.

16. A process according to claim 1 , wherein the precursor solution containing the dopant(s) is one of:
supplied to a nozzle and sprayed on to the heated substrate;
the dopant(s) is/are supplied to a nozzle separately from the precursor solution or dispersion containing the metal complex and the dopant(s) is/are mixed with the precursor solution or dispersion containing the metal complex at the nozzle immediately before spraying; or
one or more solutions or dispersions containing the dopant(s) is/are sprayed from one or more different nozzles from the precursor solution or dispersion containing the metal complex, such that the solutions or dispersions mix together as they are sprayed on to the substrate.

17. A process according to claim 1 , wherein the method comprises a step of preparing the precursor solution.

Assignees

• Univ Oxford Innovation Ltd

Inventors

• Edwards Peter
• Dilworth Jonathan
• Kuznetsov Vladimir
• Hayes Catherine

Classifications

• C01G1/02

  Oxides · CPC title

• C01B13/34

  by oxidation or hydrolysis of sprayed or atomised solutions · CPC title

• C01P2002/84

  by UV- or VIS- data · CPC title

• C01G31/02

  Oxides · CPC title

• C01P2002/72

  by d-values or two theta-values, e.g. as X-ray diagram · CPC title