Nanocrystalline Eu3+ doped-yttrium oxide dispersed onto silica prepared by a deposition-precipitation method

A deposition-precipitation technique was successful for the obtainment of Eu3+ doped-yttria/silica nanocomposites. The method is based on the impregnation of mesoporous commercial silica with a solution of yttrium and europium nitrates in the presence of urea. Urea slow hydrolysis implies the gradual deposition of yttrium-europium hydroxides onto silica. Y2O3 crystalline particles, with mean size of 7.5 nm, form over the silica matrix after calcination of the impregnated system at 900 degreesC, as evidenced by XRD and TEM. The nanoparticles slightly interact at the interface with silica, as revealed by Si-29 NMR/MAS spectroscopy. At 1000 degreesC the composite evolves toward the formation of Y2Si2O7 crystalline phase. (C) 2003 Elsevier Science Ltd. All rights reserved.