Modifications induced by acetylacetone in properties of sol–gel derived Y3Al5O12 : Tb3+ – I: structural and morphological organizations

Abstract

Acetylacetone has been used as a chemical modifier for the synthesis of undoped and Tb³⁺-doped Y₃Al₅O₁₂ powders. A systematic investigation concerning its influence on the structural and morphological properties of amorphous and crystallized samples has been carried out. These properties have been comparatively studied by means of X-ray diffraction, infrared spectroscopy, SEM, XAS and SAXS. ²⁷Al NMR and EPR experiments have been performed to complete the study. The combined results have evidenced that acetylacetone promotes organic groups departure during calcination, entailing a better structural organization at lower temperatures compared with unmodified powders. Structuration has been proven to occur at short-scale range until a 600 °C heating treatment before being extended by coalescence at higher temperatures. Finally, the presence of acac ligands on the alkoxides leads to a monomer-cluster aggregation process, and thus to a more open network.