Single-source precursor and homometal approaches to the sol–gel synthesis of iron and titanium oxides

Conference paper
Part of the Progress in Colloid and Polymer Science book series (PROGCOLLOID, volume 128)


The recently described titanium and iron heterometal isopropoxide, [FeCl{Ti2(OPr i )9}] (complex 1), has been used as a single-source sol–gel precursor to produce mixed TiO2/Fe2TiO5 materials. The products were dried and submitted to thermal treatment from 55 to 1,000 °C. Oxide composition and phase transitions were studied by X-ray powder diffractometry and Raman, electron paramagnetic resonance and Mössbauer spectroscopies. A mixture of nanometric-size TiO2 (anatase, 4.3–6.1 nm) and amorphous iron(III) oxide was obtained up to 500 °C, while TiO2 (rutile), α-Fe2O3 (hematite) and Fe2TiO5 (pseudobrookite) were found at 700 °C. At 1,000 °C, only rutile and pseudobrookite were observed. These results are very similar to those obtained by a homometallic approach from a 1:2 mixture of FeCl2 and [Ti(OPr i )4]. Scanning electron microscopy/energy-dispersive X-ray spectroscopy results for the powder obtained from complex 1 at 1,000 °C showed no phase segregation at a submicrometre level. The average chemical composition of different grains confirms the complete conversion of 1 to the metal oxides. The solids obtained from the homometal precursors present significant phase segregation. This indicates that complex 1 can generate oxide–oxide (nano)composites with a degree of homogeneity that cannot be achieved by an analogous multicomponent route.


Sol–gel Single-source precursor Heterometal oxides Titanium Iron 


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Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  1. 1.Departamento de QuímicaUniversidade Federal do Paraná, Centro PolitécnicoCuritibaBrazil
  2. 2.Department of Biological ChemistryJohn Innes Centre, Norwich Research ParkNorwichUK
  3. 3.Department of ChemistryUniversity of SussexBrightonUK
  4. 4.Departamento de Físico-QuímicaInstituto de Química de São Carlos, Universidade de São PauloSão CarlosBrazil

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