Controllable one-pot synthesis of uniform colloidal TiO₂ particles in a mixed solvent solution for photocatalysis

This study reports on the controllable synthesis of uniform colloidal titanium dioxide (TiO₂) particles and their photocatalytic applications toward rhodamine B (RhB) degradation. The monodispersed TiO₂ particles were synthesized under mixed solvent conditions by sol-gel chemistry in a one-pot process. Varying the ratio of solvent composition, the concentration of surfactant and TiO₂ precursor was used to control the particle diameter, degree of monodispersity and morphology. The modification of the calcination temperature affected the crystallinity and crystalline phase of the colloidal TiO₂ particles. When uniform, amorphous TiO₂ particles were calcined at an optimal temperature (500 °C), the final sample exhibited beneficial characteristics such as high anatase crystallinity with a mixed phase of anatase and rutile and relatively high surface area. The photocatalytic efficiency of the uniform TiO₂ sample with high anatase crystallinity with mixed phase and high surface area was dramatically enhanced towards RhB degradation under UV-vis irradiation. We systemically discuss the relationship between the synthetic parameters in our synthesis and the properties of the final TiO₂ products, as well as the crystalline properties and performance enhancement of TiO₂ photocatalysts calcined at different temperatures.