Articulo
Intercluster porous nanocomposites from combination of [AlO₄ Al₁₂(OH)₂₄(H₂O)₁₂]⁷⁺ cation and Anderson-type [Al₁₋ₓ Crₓ Mo₆O₂₄H₆]³⁻ anion: XRD, TG-DTA, SEM-EDAX and EPR studies
Registro en:
issn:1380-2224
issn:1573-4854
Autor
Cabello, Carmen Inés
Botto, Irma Lía
Filace, Ricardo Julián
Cordischi, Dante
Minelli, Giuliano
Occhiuzzi, Manlio
Porta, Piero
Institución
Resumen
The synthesis of intercluster porous nanocomposites obtained from polyoxometallate compounds such as the [AlO₄Al₁₂(OH)₂₄(H₂O)₁₂] ⁷⁺ cation (named Al₁₃) and the Anderson-type [Al₁₋ₓ Crₓ Mo₆O₂₄H₆ ]³⁻ anion [Al₁₋ₓ Crₓ Mo₆O₂₄H₆] has been performed in order to study the interaction between the two cluster ions, the stability of the XMo₆ planar configuration, the products obtained after thermal treatment, the structure and the local symmetry of the Cr³⁺ species. Chemical, thermal, structural and spectroscopic characterizations of the original and thermally treated phases have been followed by different techniques such as TG-DTA, XRD, SEM-EDAX, and mainly by EPR.
All the results have shown that the structure of the intercluster nanocomposites (Al₁₃)(Al₁₋ₓ Crₓ Mo₆)₂ precursors is similar to that reported by Son et al. for the chromium-free (Al₁₃)(AlMo₆)₂ intercluster nanocomposite [Son et al., J.
Am. Chem. Soc. 122 (2000) 7432]. After thermal treatment in air at several temperatures of the (Al₁₃)(Al₁₋ₓ Crₓ Mo₆)₂ nanocomposites the following phases have been observed and characterised: (i) at 400 ºC an amorphous phase containing dispersed Cr³⁺ ions; (ii) at 700 C a crystalline phase corresponding to Cr₂(MoO₄)₃/Al₂(MoO₄)₃ solid solutions; (iii) at 950 ºC αAl₂O₃/Cr₂O₃ solid solutions with a random dispersion of the Cr³⁺ ions. Centro de Investigación y Desarrollo en Ciencias Aplicadas Centro de Química Inorgánica