resumo
A nonaqueous route based on the solvothermal reaction of alkaline earth precursors with aluminium isopropoxide in benzyl alcohol is introduced. This simple process leads to crystalline complex nanostructures of alkaline earth aluminates, which, up to now, could only be obtained by solid state reaction at temperatures above 1100 degrees C or by sol-gel and further calcination at temperatures only slightly lower (similar to 800 degrees C). The approach appears to be rather general since under the same reaction conditions BaAl(2)O(4), CaAl(4)O(7), and SrAl(4)O(7) could be obtained. The as-synthesized materials were characterized by X-ray diffraction, electron microscopy techniques, solid-state NMR and FT-IR spectroscopies. The reaction mechanism, which was Studied as well, indicates the in-situ formation of benzoate species. These call preferentially bind to particular crystallographic facets of the aluminates via bridging bonds, thereby stabilizing the surfaces that give rise to the peculiar complex structure of the final material. In order to supplement the synthesis approach and to investigate the formation of impurity phases, pure aluminium oxide hybrid nanostructures were synthesized under similar conditions and fully characterized.
palavras-chave
SOL-GEL ROUTES; METAL-OXIDE NANOPARTICLES; STRONTIUM ALUMINATE; OPTICAL-PROPERTIES; MESOCRYSTALS; NANOCRYSTALS; TEMPERATURE; MECHANISM; SRAL2O4
categoria
Chemistry; Science & Technology - Other Topics; Materials Science; Physics
autores
Karmaoui, M; Willinger, MG; Mafra, L; Herntrich, T; Pinna, N
nossos autores
Luís Mafra
Investigador Principal
Mohamed Karmaoui
Bolseiro de pós-Doutoramento
Nicola Pinna
Investigadoragradecimentos
This work was partially supported by the WCU (World Class University) program through the Korea Science and Engineering Foundation funded by the Ministry of Education, Science and Technology (400-2008-0230).