Fabrication of tunable core-shell structured TiO₂ mesoporous microspheres using linear polymer polyethylene glycol as templates

Mesoporous core-shell structured titanium dioxide (TiO₂) microspheres were successfully prepared by a facile one-step hydrothermal method using polyethylene glycol (PEG, MW 2000) as the soft template. The products were characterized in light of the morphology and chemical composition using scanning electron microscopy, transmission electron microscopy, and X-ray powder diffraction (XRD) techniques. The XRD patterns show that the direct hydrothermal synthesized product is anatase titanium dioxide. The Brunauer-Emmett-Teller surface area is 113.8 m²/g, and the average pore size is 5.78 nm. In addition, the morphology evolution of core-shell structured titanium dioxide with the different hydrothermal times was also studied. Research shows that the shell morphology and the core size of the core-shell TiO₂ spheres can be easily tuned by controlling the hydrothermal time through the Ostwald ripening process. A possible growth mechanism of the mesoporous core-shell structured TiO₂ hollow microspheres was also proposed in this paper.