Zr and Hf oxoclusters as building blocks for the preparation of nanostructured hybrid materials and binary oxides MO2–SiO2(M = Hf, Zr)

摘要: Silica materials embedding ZrO2 or HfO2 were prepared by copolymerisation of organically modified oxozirconium oxohafnium clusters M4O2(OMc)12 (M = Zr, Hf and OMc methacrylate) with (methacryloxymethyl)triethoxysilane (methacryloxypropyl)trimethoxysilane. Free radical the oxoclusters bearing 12 methacrylate groups methacrylate-functionalized siloxanes allows stable anchoring to silica network formed hydrolysis condensation alkoxy groups. This route represents a valuable strategy yield very homogeneous dispersion MO2 precursors inside matrix. The composition microstructural features starting hybrid gels studied solid state 13C 29Si NMR spectroscopy FT IR transmission spectroscopy. Their evolution upon mild heating (up 180 °C) was followed FT-IR Attenuated Total Reflectance (ATR), while their thermal behaviour thermogravimetric analysis (TGA). covalent incorporation into matrix at several temperatures. Through X-Ray Diffraction (XRD) Extended X-ray Absorption Fine Structure Spectroscopy (EXAFS) it is demonstrated that temperatures above 800 °C binary oxides MO2–SiO2 (M Hf). Delayed crystallisation tetragonal from 450 least detected, which ascribed presence guest oxide in