FUEL ADDITIVE CONTAINING LATTICE ENGINEERED CERIUM DIOXIDE NANOPARTICLES

• US 20120124899A1
• Filed: 12/17/2008
• Published: 05/24/2012
• Est. Priority Date: 09/05/2006
• Status: Active Grant

• Current Assignee: Cerion, LLC (Revstone Industries LLC)
• Original Assignee: Cerion Technology, Inc.
• Inventors: Difrancesco, Albert Gary, Allston, Thomas D., Langner, Andreas, Reed, Kenneth J., Hailstone, Richard K., Langner, Linda
• Granted Patent: US 10,435,639 B2
• Time in Patent Office: Days
• US Class Current: 44/457
• 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 23/83 with rare earths or actinides
• CPC Class Codes: B01J 2523/00 Constitutive chemical elements of heterogeneous catalysts
• CPC Class Codes: B01J 2523/3712 Cerium
• CPC Class Codes: B01J 2523/48 Zirconium
• CPC Class Codes: B01J 2523/842 Iron
• CPC Class Codes: B01J 35/00 Catalysts, in general, characterised by their form or physical properties
• CPC Class Codes: B01J 35/23 in a colloidal state
• CPC Class Codes: B01J 35/393 Metal or metal oxide crystallite size
• CPC Class Codes: B01J 37/031 Precipitation
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C10L 1/1241 metal carbonyls
• CPC Class Codes: C10L 2200/0245 Lanthanide group metals: La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu
• CPC Class Codes: C10M 103/06 Metal compounds
• CPC Class Codes: C10M 177/00 Special methods of preparation of lubricating compositions; Chemical modification by after-treatment of components or of the whole of a lubricating composition, not covered by other classes
• CPC Class Codes: C10N 2010/06 Groups 3 or 13

Abstract

A process for making cerium dioxide nanoparticles containing at least one transition metal (M) utilizes a suspension of cerium hydroxide nanoparticles prepared by mechanical shearing of an aqueous mixture containing an oxidant in an amount effective to enable oxidation of cerous ion to ceric ion, thereby forming a product stream that contains transition metal-containing cerium dioxide nanoparticles, Ce_1-xM_xO₂, wherein “x” has a value from about 0.3 to about 0.8. The nanoparticles thus obtained have a cubic fluorite structure, a mean hydrodynamic diameter in the range of about 1 nm to about 10 nm, and a geometric diameter of less than about 4 nm. The transition metal-containing crystalline cerium dioxide nanoparticles can be used to prepare a dispersion of the particles in a nonpolar medium.

Claims

1. A process for making lattice engineered crystalline cerium dioxide nanoparticles containing at least one transition metal (M), said process comprising:

(a) providing an aqueous reaction mixture comprising a source of cerous ion, a source of one or more transition metal ions (M), a source of hydroxide ion, at least one nanoparticle stabilizer, and an oxidant at an initial temperature in the range of about 20°

C. to about 95°

C.;

(b) mechanically shearing said mixture and causing it to pass through a perforated screen, thereby forming a homogeneously distributed suspension of cerium hydroxide nanoparticles; and

(c) providing temperature conditions effective to enable Oxidation of cerous ion to ceric ion, thereby forming a product stream comprising transition metal-containing cerium dioxide nanoparticles, Ce_1-xM_xO₂, wherein “

x”

has a value from about 0.3 to about 0.8, said nanoparticles having a crystalline cubic fluorite structure, a mean hydrodynamic diameter in the range of about 1 nm to about 10 nm and a geometric diameter in the range of about 1 nm to about 4 nm.

2. The process according to claim 1 wherein said mechanical shearing is effected in a colloid mill.

3. The process according to claim 1 wherein said temperature conditions effective to enable oxidation of cerous ion to ceric ion comprise a temperature of about 50°

C. to about 100°

C.

4. The process according to claim 3 wherein said temperature conditions effective to enable oxidation of cerous ion to ceric ion comprise a temperature of about 60°

C. to about 90°

C.

5. The process according to claim 1 wherein said sources of ions are introduced into said reaction mixture either concurrently or sequentially during said mechanical shearing.

6. The process according to claim 1 wherein said cerium dioxide nanoparticles have a mean hydrodynamic diameter of about 6 nm.

7-26. -26. (canceled)

27. A process for forming a homogeneous dispersion containing stabilized lattice engineered transition metal-containing crystalline cerium dioxide nanoparticles, Ce_1-xM_xO₂, said process comprising:

(a) providing an aqueous mixture that includes stabilized transition metal doped cerium dioxide nanoparticles, Ce_1-xM_xO₂, having a cubic fluorite structure, said nanoparticles having a mean hydrodynamic diameter in the range of about 1 nm to about 10 nm and a geometric diameter of less than about 4 nm;

(b) concentrating said aqueous mixture that includes said stabilized transition metal-containing cerium dioxide nanoparticles, thereby forming an aqueous concentrate;

(c) removing substantially all the water from said aqueous concentrate, thereby forming a substantially water-free concentrate of said stabilized transition metal-containing cerium dioxide nanoparticles;

(d) adding an organic diluent to said substantially water-free concentrate, thereby forming an organic concentrate of said stabilized transition metal-containing cerium dioxide nanoparticles; and

(e) combining said organic concentrate with a surfactant in the presence of a nonpolar medium, thereby forming said homogeneous dispersion containing stabilized transition metal-containing crystalline cerium dioxide nanoparticles, Ce_1-xM_xO₂.

28. The process according to claim 27 wherein said transition metal M in said transition metal-containing cerium dioxide nanoparticles, Ce_1-xM_xO₂, is selected from the group consisting of Fe, Mn, Cr, Ni, W, Co, V, Cu, Zr, Y, Mo, and combinations thereof.

29. The process according to claim 28 wherein “

x”

has a value of about 0.30 to about 0.80.

30. The process according to claim 29 wherein “

x”

has a value of about 0.40 to about 0.60.

31. The process according to claim 28 wherein said transition metal M comprises Zr or Y.

32. The process according to claim 31 wherein said transition metal M further comprises Fe.

33. The process according to claim 27 wherein said organic diluent comprises a glycol ether.

46. A wash coat for a catalytic converter of an internal combustion engine exhaust system, said wash coat being produced using the homogeneous dispersion containing stabilized transition metal-containing crystalline cerium dioxide nanoparticles formed according to claim 27.

47. A catalyst effective for accelerating a reduction reaction or an oxidation reaction, said catalyst being produced using the homogeneous dispersion containing stabilized transition metal-containing crystalline cerium dioxide nanoparticles formed according to claim 27.

34-45. -45. (canceled)