Sol–gel synthesis of composite powders in the TiO2–TeO2–SeO2 system

The aim of this paper is to study the gel formation tendency in the TiO 2 –TeO 2 –SeO 2 system. Telluric acid (H 6 TeO 6 ), selenous acid (H 2 SeO 3 ) and titanium butoxide were used as precursors dissolved in ethylene glycol. Transparent monolithic and bright yellow colored gels are situated between 40–100 mol% TiO 2 , up to 20 mol% SeO 2 and 65 mol% TeO 2 . The phase transformations of the as-prepared gels heat-treated up to 700 °C are investigated by XRD. The chemical states of C, Ti, Se and Te are characterized by means of XPS. Organic and OH groups participate in the amorphous organic–inorganic structure up to 250–300 °C. The structure of the inorganic amorphous phases above 300 °C consists of SeO 3 , TiO 6 and TeO n structural units. The UV–Vis spectra of the binary and three-component gels exhibited a redshift of the cutoff in comparison with those of Ti butoxide gel due to the presence of selenium and tellurium units. Graphical Abstract Gel formation region in the ternary TiO 2 –TeO 2 –SeO 2 system