Abstract: Aqueous and substantially crystalline iron oxide nanoparticle dispersions and processes for making them are disclosed. The nanoparticle size and size distribution width are advantageous for use in a fuel additive for catalytic reduction of soot combustion in diesel particulate filters. Nanoparticles of the aqueous colloid are transferred to a substantially non-polar liquid comprising a carboxylic acid and one or more low-polarity solvents. The transfer is achieved by mixing the aqueous and substantially non-polar materials, forming an emulsion, followed by a phase separation into a substantially metal-free remnant polar phase and a substantially non-polar organic colloid phase. A method for rapid and substantially complete transfer of non-agglomerated nanoparticles to the low polarity phase in the presence of an organic amine, and a rapid phase separation of the substantially non-polar colloid from a remnant aqueous phase, are provided.

Abstract: A process for forming alkaline earth metal cerate nanoparticles comprises combining a stable cerium oxide aqueous colloidal dispersion with soluble alkaline earth metal salts while maintaining colloidal stability. The resulting alkaline earth metal salts may be calcined to form alkaline earth metal cerate particles having a perovskite structure.

Abstract: A method of making cerium-containing metal oxide nanoparticles in non-polar solvent eliminates the need for solvent shifting steps. The direct synthesis method involves: (a) forming a reaction mixture of a source of cerous ion and a carboxylic acid, and optionally, a hydrocarbon solvent; and optionally further comprises a non-cerous metal ion; (b) heating the reaction mixture to oxidize cerous ion to ceric ion; and (c) recovering a nanoparticle of either cerium oxide or a mixed metal oxide comprising cerium. The cerium-containing oxide nanoparticles thus obtained have cubic fluorite crystal structure and a geometric diameter in the range of about 1 nanometer to about 20 nanometers. Dispersions of cerium-containing oxide nanoparticles prepared by this method can be used as a component of a fuel or lubricant additive.

Abstract: A process for forming alkaline earth metal cerate nanoparticles comprises combining a stable cerium oxide aqueous colloidal dispersion with soluble alkaline earth metal salts while maintaining colloidal stability. The resulting alkaline earth metal salts may be calcined to form alkaline earth metal cerate particles having a perovskite structure.

Abstract: Aqueous and substantially crystalline iron oxide nanoparticle dispersions and processes for making them are disclosed. The nanoparticle size and size distribution width are advantageous for use in a fuel additive for catalytic reduction of soot combustion in diesel particulate filters. Nanoparticles of the aqueous colloid are transferred to a substantially non-polar liquid comprising a carboxylic acid and one or more low-polarity solvents. The transfer is achieved by mixing the aqueous and substantially non-polar materials, forming an emulsion, followed by a phase separation into a substantially metal-free remnant polar phase and a substantially non-polar organic colloid phase. A method for rapid and substantially complete transfer of non-agglomerated nanoparticles to the low polarity phase in the presence of an organic amine, and a rapid phase separation of the substantially non-polar colloid from a remnant aqueous phase, are provided.

Abstract: A method of making cerium-containing metal oxide nanoparticles in non-polar solvent eliminates the need for solvent shifting steps. The direct synthesis method involves: (a) forming a reaction mixture of a source of cerous ion and a carboxylic acid, and optionally, a hydrocarbon solvent; and optionally further comprises a non-cerous metal ion; (b) heating the reaction mixture to oxidize cerous ion to ceric ion; and (c) recovering a nanoparticle of either cerium oxide or a mixed metal oxide comprising cerium. The cerium-containing oxide nanoparticles thus obtained have cubic fluorite crystal structure and a geometric diameter in the range of about 1 nanometer to about 20 nanometers. Dispersions of cerium-containing oxide nanoparticles prepared by this method can be used as a component of a fuel or lubricant additive.