Template-free hydrothermal synthesis of macroporous TiO2 microspheres on a large scale

Macroporous TiO2 microspheres have been synthesized on a large scale by a facile hydrothermal process using titanium tetrachloride (TiCl4) as the titanium source, ammonium fluoride (NH4F) and hydrogen peroxide (H2O2) as the etchant. X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM) studies show that the anatase TiO2 microspheres are well-crystalline with an average diameter of 5.43 μm. N2 adsorption–desorption and mercury intrusion porosimetry analysis reveal that the as-prepared TiO2 microspheres are composed of numerous pore networks with an average pore diameter of 274 nm and porosity of 39.8%. In addition, the formation mechanisms of macroporous TiO2 microspheres were also investigated.