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, Ce1-xMxO2, 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.

Abstract: A method of making cerium dioxide nanoparticles includes: a) providing an aqueous reaction mixture having a source of cerous ion, a source of hydroxide ion, a nanoparticle stabilizer, and an oxidant at an initial temperature no higher than about 20° C.; b) mechanically shearing the mixture and causing it to pass through a perforated screen, thereby forming a suspension of cerium hydroxide nanoparticles; and c) raising the initial temperature to achieve oxidation of cerous ion to eerie ion and thereby form cerium dioxide nanoparticles having a mean diameter in the range of about 1 nm to about 15 nm. The cerium dioxide nanoparticles may be formed in a continuous process.

Abstract: A method of making a structured, doped, cerium oxide nanoparticle includes (a) forming a first reaction mixture including cerium(III), an optional metal ion other than cerium, a base, a stabilizer, and a solvent, (b) contacting the first reaction mixture with an oxidant, (c) forming a cerium oxide nanoparticle core by heating the product of step (b), (d) forming a second reaction mixture by combining with the first reaction mixture one or more metal ions other than cerium, and an optional additional quantity of cerium(III), and (e) forming a shell surrounding the core of cerium oxide by heating the second reaction mixture to produce a product dispersion of structured cerium oxide nanoparticles.

Abstract: A process for making cerium-containing oxide nanoparticles includes providing an aqueous reaction mixture containing a source of cerous ion and a source of one or more metal ions (M) other than cerium, a source of hydroxide ion, at least one monoether carboxylic acid nanoparticle stabilizer wherein the molar ratio of said monoether carboxylic acid nanoparticle stabilizers to total metal ions is greater than 0.2, and an oxidant. The cerous ion is oxidized to ceric ion, thereby forming a product dispersion of cerium-containing oxide nanoparticles containing one or more metal ions (M), Ce1-xMxO2-?, wherein x has a value from about 0.001 to about 0.95 and ? has a value of about 0.0 to about 0.5.

Abstract: A process for making cerium-containing oxide nanoparticles includes providing an aqueous reaction mixture containing a source of cerous ion, a source of hydroxide ion, at least one monoether carboxylic acid wherein the molar ratio of said monoether carboxylic acid to cerous ions is greater than 0.2, and an oxidant. The cerous ion is oxidized to ceric ion, thereby forming a product dispersion of cerium-containing oxide nanoparticles CeO2-?, wherein ? has a value of about 0.0 to about 0.5.

Abstract: A process for making cerium-containing oxide nanoparticles includes providing an aqueous reaction mixture containing a source of cerous ion, optionally a source of one or more metal ions (M) other than cerium, a source of hydroxide ion, at least one monoether carboxylic acid nanoparticle stabilizer wherein the molar ratio of said monoether carboxylic acid nanoparticle stabilizers to cerous ions is greater than 0.2, and an oxidant. The cerous ion is oxidized to ceric ion, thereby forming a product dispersion of cerium-containing oxide nanoparticles CeO2-?, wherein ? has a value of about 0.0 to about 0.5. The nanoparticles may have a mean hydrodynamic diameter from about 1 nm to about 50 nm, and a geometric diameter of less than about 45 nm.

Abstract: A process for making cerium-containing oxide nanoparticles includes providing an aqueous reaction mixture containing a source of cerous ion, optionally a source of one or more metal ions (M) other than cerium, a source of hydroxide ion, at least one monoether carboxylic acid nanoparticle stabilizer wherein the molar ratio of said monoether carboxylic acid nanoparticle stabilizers to total metal ions is greater than 0.2, and an oxidant. The cerous ion is oxidized to ceric ion, thereby forming a product dispersion of cerium-containing oxide nanoparticles, optionally containing one or more metal ions (M), Ce1-xMxO2-?, wherein x has a value from about 0.001 to about 0.95 and ? has a value of about 0.0 to about 0.5. The nanoparticles may have a mean hydrodynamic diameter from about 1 nm to about 50 nm, and a geometric diameter of less than about 45 nm.

Abstract: A process for making cerium-containing oxide nanoparticles includes providing an aqueous reaction mixture containing a source of cerous ion, optionally a source of one or more metal ions (M) other than cerium, a source of hydroxide ion, at least one monoether carboxylic acid nanoparticle stabilizer wherein the molar ratio of said monoether carboxylic acid nanoparticle stabilizers to total metal ions is greater than 0.2, and an oxidant at an initial temperature in the range of about 20° C. to about 95° C. Temperature conditions are provided effective to enable oxidation of cerous ion to ceric ion, thereby forming a product dispersion of cerium-containing oxide nanoparticles, optionally containing one or more metal ions (M), Ce1-xMxO2-?, wherein “x” has a value from about 0.0 to about 0.95. The nanoparticles may have a mean hydrodynamic diameter from about 1 nm to about 50 nm, and a geometric diameter of less than about 45 nm.

Abstract: A method of making a structured, doped, cerium oxide nanoparticle includes (a) forming a first reaction mixture including cerium(III), an optional metal ion other than cerium, a base, a stabilizer, and a solvent, (b) contacting the first reaction mixture with an oxidant, (c) forming a cerium oxide nanoparticle core by heating the product of step (b), (d) forming a second reaction mixture by combining with the first reaction mixture one or more metal ions other than cerium, and an optional additional quantity of cerium(III), and (e) forming a shell surrounding the core of cerium oxide by heating the second reaction mixture to produce a product dispersion of structured cerium oxide nanoparticles.

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, Ce1-xMxO2, 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.

Abstract: A method of making cerium dioxide nanoparticles includes: a) providing an aqueous reaction mixture having a source of cerous ion, a source of hydroxide ion, a nanoparticle stabilizer, and an oxidant at an initial temperature no higher than about 20° C.; b) mechanically shearing the mixture and causing it to pass through a perforated screen, thereby forming a suspension of cerium hydroxide nanoparticles; and c) raising the initial temperature to achieve oxidation of cerous ion to eerie ion and thereby form cerium dioxide nanoparticles having a mean diameter in the range of about 1 nm to about 15 nm. The cerium dioxide nanoparticles may be formed in a continuous process.