Yttrium Oxide Nanoparticles Prepared by Alkalide Reduction

Y 2 O 3 nanoparticles have been synthesized by subambient homogeneous reduction using alkalide solutions and subsequent oxidation. As synthesized, the material consists of free flowing, well-defined 1−3 nm particles. Annealing in air at temperatures between 100 and 400 °C results in transformation of the material to irregular particles that are strongly agglomerated. Samples annealed between 500 and 800 °C consist of rather irregular, ill-defined, agglomerated particles while those heated to 900 °C consist of well-defined spheroids. Sintering occurs at temperatures as low as 100 °C, and crystallization is not observed until 500 °C. Samples annealed at 200 °C have surface areas of 109 m 2 /g. Raising the annealing temperature from 500 to 900 °C results in a decrease of the surface area from 84 to 25 m 2 /g while increasing the average crystallite size from 11.8 to 20.1 nm.