Method of preparing cerium dioxide nanoparticles

A process for making cerium dioxide nanoparticles comprising the steps of:

• providing an aqueous reaction mixture comprising a source of cerous ion, a source of hydroxide ion, a water soluble nanoparticle stabilizer comprising an alkoxylated carboxylic acid, or salt thereof, and an oxidant;
• and
• providing temperature conditions effective to enable oxidation of cerous ion to ceric ion, wherein said temperature conditions effective to enable oxidation of cerous ion to ceric ion comprise a temperature less than 100° C., thereby forming a product dispersion comprising cerium dioxide nanoparticles, wherein said nanoparticles are characterized by a crystalline cubic fluorite structure,
• wherein said water soluble nanoparticle stabilizer comprises a compound of formula (Ia),
• R—O—(CH2CH2O)nCHR1CO2Y (Ia)
• wherein:
• R represents a methyl group or an ethyl group;
• R1 represents hydrogen or an alkyl group;
• Y represents H or a counterion;
• and
• n is 0-5.