Effect of titanium additives on the growth of tellurium dioxide crystals in a sol–gel process

Hydrolysis of tellurium isopropoxide, in the presence of tetraalkylammonium bromide solution, led to oriented α-TeO2 crystals. Anisotropic growth was enhanced by adding trace amounts of titanium isopropoxides which allowed to get higher aspect ratio α-TeO2 crystals. Higher amounts of titanium isopropoxides afforded mixtures of α-TeO2 rods and β-TeO2 square crystals or TiTe3O8 crystalline materials after annealing at 480 °C. Those materials have been characterised by FT-IR, XRD, XPS and SEM-EDX techniques.