Metal oxide nanoparticles and process for producing the same

• US 20070075052A1
• Filed: 06/08/2006
• Published: 04/05/2007
• Est. Priority Date: 06/08/2005
• Status: Active Grant

• Current Assignee: UNM Rainforest Innovations (f/k/a STC.UNM) (The University of New Mexico), Toyota Motor Corporation, TRIAD National Security, LLC
• Original Assignee: Toyota Motor Corporation
• Inventors: Phillips, Jonathan, Luhrs, Claudia, Fanson, Paul
• Granted Patent: US 7,629,553 B2
• Time in Patent Office: Days
• US Class Current: 219/121.520
• CPC Class Codes: B01J 23/002 Mixed oxides other than spinels, e.g. perovskite
• CPC Class Codes: B01J 23/10 of rare earths
• CPC Class Codes: B01J 2523/00 Constitutive chemical elements of heterogeneous catalysts
• CPC Class Codes: B01J 2523/31 Aluminium
• CPC Class Codes: B01J 2523/3712 Cerium
• CPC Class Codes: B01J 2523/48 Zirconium
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C01B 13/185 Preparing mixtures of oxides
• CPC Class Codes: C01F 17/235 Cerium oxides or hydroxides
• CPC Class Codes: C01F 17/34 Aluminates, e.g. YAlO3 or Y3-xGdxAl5O12
• CPC Class Codes: C01G 1/00 Methods of preparing compounds of metals not covered by subclasses C01B, C01C, C01D, or C01F, in general electrolytic production of inorganic compounds C25B1/00
• CPC Class Codes: C01G 1/02 Oxides
• CPC Class Codes: C01G 23/047 Titanium dioxide
• CPC Class Codes: C01G 25/00 Compounds of zirconium
• CPC Class Codes: C01G 25/02 Oxides
• CPC Class Codes: C01P 2002/34 perovskite-type (ABO3)
• CPC Class Codes: C01P 2002/72 by d-values or two theta-values, e.g. as X-ray diagram
• CPC Class Codes: C01P 2004/03 obtained by SEM
• CPC Class Codes: C01P 2004/04 obtained by TEM, STEM, STM or AFM
• CPC Class Codes: C01P 2004/32 Spheres
• CPC Class Codes: C01P 2004/34 : hollow
• CPC Class Codes: C01P 2004/53 : bimodal size distribution
• CPC Class Codes: C01P 2004/64 : Nanometer sized, i.e. from 1-100 nanometer
• CPC Class Codes: C01P 2004/82 : two phases having the same anion, e.g. both oxidic phases
• CPC Class Codes: C01P 2004/84 : one phase coated with the other
• CPC Class Codes: C01P 2006/12 : Surface area
• CPC Class Codes: C09C 1/3661 : Coating
• CPC Class Codes: Y10T 428/2991 : Coated

Abstract

There is disclosed a process for producing metal oxide nanoparticles. The process includes the steps of: a) providing at least two precursor metal salt materials, b) passing the at least two precursor metal salt materials through a plasma torch forming a vaporized material, and then c) condensing the vaporized material forming a metal oxide nanoparticle.

Claims

1. A process for producing metal oxide nanoparticles comprising the steps of:

a) providing at least two precursor metal salt materials;

b) passing the at least two precursor metal salt materials through a plasma torch forming a vaporized material;

c) condensing the vaporized material forming a metal oxide nanoparticle.

2. The process of claim 1 wherein the precursor metal salt material is selected from the group consisting of:

salts of magnesium, aluminum, silicon, titanium, iron, copper, zinc, yttrium, zirconium, lanthanum, cerium, praseodymium, neodymium, or dysprosium.

3. The process of claim 2 wherein the salts comprise nitrates.

4. The process of claim 2 wherein the salts comprise acetates.

5. The process of claim 2 wherein the precursor metal salt material is a dry powder.

6. The process of claim 5 wherein the dry powder has a particle size of from 100 nm to 5 mm.

7. The process of claim 2 wherein the dry powder is formed from a solution of precipitated salts of the metal precursor followed by drying and crushing to form the dry powder.

8. The process of claim 2 wherein the precursor metal salt material is a liquid.

9. The process of claim 8 wherein the liquid includes the salt dissolved in a solvent.

10. The process of claim 9 wherein the solvent is selected from the group consisting of:

water, organic non-polar liquids, organic polar liquids, ethers and acids.

11. The process of claim 1 wherein the metal precursor salt material is dispersed in a carrier gas.

12. The process of claim 11 wherein the carrier gas is selected from the group consisting of:

noble gases, oxygen, and nitrogen or mixtures thereof.

13. The process of claim 11 wherein the carrier gas has a flow rate of from 1 cm³/min to 10 L/min.

14. The process of claim 1 wherein the plasma is generated using a DC discharge, radio frequency energy or microwave energy.

15. The process of claim 1 wherein the plasma is generated using a power of from 200 to 100,000 Watts.

16. The process of claim 1 wherein the plasma torch has a temperature greater than 3000 degrees centigrade.

17. The process of claim 1 wherein the nanoparticles formed include solid solution particles, hollow particles, core-shell particles and particles having a variegated surface.

18. The process of claim 1 including the step of exposing the nanoparticles to a reducing atmosphere at an elevated temperature forming a perovskite material.

19. The process of claim 1 including the step of separating the nanoparticles into desired sizes.

20. The process of claim 1 wherein the nanoparticle has a surface area of from 1 m²/gram to 500 m²/gram.

21. The process of claim 1 wherein the precursor metal salt materials comprise a salt of aluminum and a salt of cerium.

22. The process of claim 21 wherein the particle formed has a core of cerium oxide surrounded by a shell of aluminum oxide.

23. The process of claim 22 wherein the particle formed has a variegated surface of cerium oxide and aluminum oxide.

24. The process of claim 1 wherein the precursor metal salt materials comprise a salt of aluminum, a salt of cerium, and a salt of zirconium.

25. The process of claim 24 wherein the nanoparticle formed has a core of cerium and zirconium oxide surrounded by a shell of aluminum oxide.

26. The process of claim 1 wherein the precursor metal salt materials comprise a salt of aluminum and a salt of titanium.

27. The process of claim 26 wherein the nanoparticle formed has a core of titanium oxide surrounded by a shell of aluminum oxide.

28. The process of claim 1 wherein the precursor metal salt materials comprise a salt of cerium, and a salt of zirconium.

29. The process of claim 28 wherein the nanoparticle formed has a solid structure of cerium and zirconium oxide.

30. The process of claim 1 wherein the precursor metal salt materials comprise a salt of cerium, and a salt of titanium.

31. The process of claim 30 wherein the nanoparticle formed has a solid structure of cerium and titanium oxide.

32. The process of claim 1 wherein the precursor metal salt materials comprise a salt of zirconium, and a salt of aluminum.

33. The process of claim 32 wherein the nanoparticle formed has a solid structure of zirconium and aluminum oxide.

34. A metal oxide nanoparticle having a solid solution structure of at least two metals.

35. The metal oxide nanoparticle of claim 34 wherein the solid solution comprises zirconium and aluminum oxide.

36. The metal oxide nanoparticle of claim 34 wherein the solid solution comprises titanium and aluminum oxide.

37. The metal oxide nanoparticle of claim 34 wherein the solid solution comprises cerium and titanium oxide.

38. The metal oxide nanoparticle of claim 34 wherein the solid solution comprises zirconium and cerium oxide.

39. A metal oxide nanoparticle having a core and shell structure of at least two metals.

40. The metal oxide nanoparticle of claim 39 wherein the nanoparticle has a core of cerium oxide surrounded by a shell of aluminum oxide.

41. The metal oxide nanoparticle of claim 39 wherein the nanoparticle has a core of cerium oxide and zirconium oxide surrounded by a shell of aluminum oxide.

42. The metal oxide nanoparticle of claim 39 wherein the nanoparticle has a core of titanium oxide surrounded by a shell of aluminum oxide.

43. A metal oxide particle having a variegated surface of cerium oxide and aluminum oxide.