Template-Free Fabrication of TiO₂ Hollow Spheres and Their Photocatalytic Properties

Submicrometer-sized anatase TiO₂ hollow spheres were fabricated through a template-free solvothermal route using TiCl₄ as a raw material and a mixture of alcohols–acetone as solvent. Control of the hollow spheres’ size was achieved by adjusting the ratio of alcohols to acetone. Products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution TEM, X-ray photoelectron spectra (XPS), X-ray diffraction (XRD), Fourier transform infrared (FT-IR), and thermogravimetric (TG) analysis. It was found that the formation process of the TiO₂ hollow spheres might include the hydrolysis of Ti­(IV) with the water formed from the solvothermal etherification reaction, the aggregation of the anatase TiO₂ nanoparticles, and the Ostwald ripening. Furthermore, the as-prepared TiO₂ hollow nanostructures exhibited good photocatalytic activity for the degradation of phenol