GENERAL GROUP VI TRANSITION NANOSTRUCTURED METAL OXIDES AND THEIR INCLUSION INTO SOLID MATRICES BY A SOLUTION-SOLID APPROACH

[摘要] A facile and general solution//solid-state (SSS) approach to the synthesis of nanostructured metal oxides Cr2O3, MoO3 and WO3 was investigated. They are made from solid-state pyrolysis of the metal- macromolecular precursors PS-co-4-PVP•MCln and Chitosan•MCln with M= Cr, Mo and W, which were easily prepared by direct reaction of the salts CrCl3, MoCl4 and WCl4 with the respective polymer. The size and morphology of the products, the nanostructured oxides Cr2O3, MoO3 and WO3 depend on the polymer and on the coordination degree of the precursor. Cr2O3 as well as WO3, prepared from this method were included in silica and Titania matrix using an also solution//solid-state approximation. The nanoparticles of Cr2O3 and WO3 are in general distributed with uniformity within the amorphous silica. A probable formation mechanism of the Cr2O3, MoO3 and WO3 nanoparticles was proposed. The nanocomposites Cr2O3//SiO2 and WO3//SiO2 could be useful materials in catalysis.

[学科分类] 化学（综合）

[关键词] Solid-state;pyrolysis;nanostructured;metal oxide