Patent ID: 8883865

Claim:
A method for making a dispersion of cerium oxide nanoparticles that include at least one other metal, comprising: a) forming an aqueous reaction mixture comprising: i) a source of cerous ion and a source of one or more metal ions other than cerium, wherein said source of cerous ion and said source of one or more metal ions other than cerium are introduced into the reaction mixture concurrently; ii) a source of hydroxide ion; iii) at least one monoether carboxylic acid, wherein the molar ratio of said monoether carboxylic acid to total metal ions is greater than 0.2; and iv) an oxidant at an initial temperature in the range of about 20° C. to about 100° C.; b) maintaining the reaction mixture at a temperature permitting oxidation of cerous ion to ceric ion; and c) thereby forming in the reaction mixture a dispersion of metal-containing cerium oxide nanoparticles, Ce 1-x M x O 2-δ , wherein x has a value from about 0.001 to about 0.95; M represents said at least one other metal, and δ has a value of about 0.0 to about 0.5.