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.
Keywords: mixed solvent; one-pot synthesis; photocatalysts; rhodamine B degradation; sol–gel synthesis; spherical TiO2 particles.