Large-scale synthesis of hollow titania spheres via flame combustion

Hollow crystalline TiO2 spheres with good thermal stability were prepared by the hydrolysis of TiCl4 in the H2/air flame at about 1500 °C. The hollow spheres, with uniform diameter of 300 nm and shell thickness of 35 nm, consist of 20-30 nm TiO2 nanocrystallites. The present study provides a new pathway for continuous and large-scale engineering of hollow nanomaterials.