Patent ID: 8419974

Claim:
A method for the preparation of a nanocrystalline rare earth phosphate, the method comprising: combining in an aqueous medium (i) a phosphate source including a partially neutralized phosphoric acid, (ii) at least one water soluble salt of a primary rare earth selected from the group consisting of La, Lu, Gd, and (iii) at least one water soluble salt of an activator element selected from the group consisting of Pr, Nd, Eu, Ce, Tb, Bi, and Pb; wherein said combining is effective to form a precipitate comprising at least phosphate and the primary rare earth; and calcining the precipitate at a temperature of from about 300° C. to less than about 400° C. for a period of from about 1 h to about 10 h to form a nanocrystalline rare earth phosphate, wherein said calcining forms an activated nanocrystalline rare earth phosphate comprising at least one said activator element.