Producing rare earth metal oxide powders, e.g. useful as luminescent or colored pigments or catalyst supports, comprises heating nitrate precursors in a polar organic solvent

摘要

Producing a rare earth metal sesquioxide, oxohydroxide or hydroxide powder comprises dissolving nitrate precursors in a polar organic solvent with a boiling point above 200[deg]C in an amount of 10-500 g/l in the presence of water and heating the solution to a temperature above 170[deg]C but below the boiling point of the solvent to precipitate the powder. Producing a rare earth metal (Ln) sesquioxide, oxohydroxide or hydroxide, optionally mixed or doped with Ln or cerium, or a mixed oxide of formula (I) or (II) in the form of a mono- or polyphase powder containing more than 50 wt.% Ln, or a colloidal suspension thereof, comprises dissolving precursors of Ln and optionally A, at least 50 wt.% of which are Ln nitrates, in a polar organic solvent with a boiling point above 200 [deg]C in an amount of 10-500 g/l in the presence of water, heating the solution to a temperature above 170 [deg]C but below the boiling point of the solvent to precipitate the powder in the form of nanostructured particles with an average diameter of 20-800 nm, optionally separating and drying the powder and optionally redispersing the powder in a solvent. Ln xA 2-x(O) y(I) Ln xA 2-x(O) v(OH) z(II) Ln : Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb or Lu; A : a transition metal, B, Al, Si, P or Bi; x : 0-2; y : 3-4; v : 0-4; z : 0 to 8-2v. An independent claim is also included for a Ln 2O 3powder or a colloidal suspension thereof, optionally mixed or doped with Ln or cerium, comprising nanostructured spherical particles with an average diameter of 20-800 nm.